A commonly reported problem with the FZ5 is the lens becoming stuck in one position. This is because the cogs that drive it are made of plastic and the mounting for the lens motor is a bit flimsy. A Panasonic service centre will charge quite a bit just to look at your camera, let alone fix it, yet this is a relatively simple thing to fix if you're not afraid of dismantling things.
Of course, you do this at your own risk, not mine. I can't offer any guarantee that this will work for you, but a few people have had the same error and performed the same fix successfully. Work carefully and it should be fine. This may also be applicable for similar panasonic compacts, such as the FZ7.
(Note on photography: I captured the LCD screen and balanced it with the rest of the scene by bouncing a powerful flash off a white blanket on the floor of a small room, which also had a white ceiling. At around 1/80 - 1/100 of a sec, the 16 feet or so the flash light had to travel balanced the screen and the rest of the camera up well, and provided good diffuse lighting for the innards of the camera).
Step 1: Tools
Tray (In this case just a flipped Shogi board)
I forgot to record the sizes, I just tried out tools from sets of screwdrivers and allen keys until I found the ones that fitted best. Even though the screws on the camera are posidrives, a flat head screwdriver was the best fit.
I also swapped the tweezers pictured for some round ended ones when it came to dealing with the ribbons because I didn't want to accidentally scratch or pierce anything.
Also very useful:
The torch was handy for peering at secluded fixings, and I used a piece of scotch tape to hold screws as I removed them.
The tray was absolutely vital. If you disassemble stuff without a tray, small screws will bounce onto the floor and hide and break your heart.
Step 2: Disassembly: Housing
The first fixing to remove is an allen bolt under the flash. This, along with six screws distributed around the main seam, secures the back to the front of the camera.
Remove all six screws too, and note that three are long, three are short, and both types have different threads. You're now ready to get inside this thing...
Step 3: Disassembly: Ribbons and Cables and Screws. Oh My!
The back section, which holds the LCD and some of the controls, is connected via two ribbons and two power connectors (labelled in first photo below). The ribbon connectors have fasteners at either side that slide along the same plane as the circuit board. Gently slide them out, and you'll be able to (carefully!) remove the ribbons.
The power connectors are a little trickier; work them gently, don't yank no matter how tempted you are. Working a slim object such as a screwdriver blade between the connector and the socket may help, but make sure not to abuse the connection between the socket and the circuit board.
Now you should be able to remove the back of the camera.
Step 4: Disassembly: Remove Mainboard, etc.
There are just two screws holding this board in and a lot of the camera together, marked in the first image below. One is below the shooting mode dial, the other is below the left hand side of the flash unit. Unscrew both of these, and take note that one is longer than the other.
Now slide the upper control assembly out of the back of the housing, as shown in the second image.
Next, carefully lift out the mainboard, flash assembly, and SD/Battery socket assembly all in one piece, as shown in the third image.
Step 5: Disassembly: Final Steps
Two of the parts shown below are secured to the inside of the camera in a rather rickety fashion. The lens is very solidly fastened in place of course, but the AF/EVF assembly and the lens motor are not. They're also made of fairly soft plastic. The lens is stuck because of these flaws.
First, remove the single screw that secures the AF lamp and electronic viewfinder assembly, shown in the first image below. Then remove the two black screws that keep the lens motor in place, highlighted in image number two. Do not pull on the lens motor, it will still be fixed to the lens assembly by the ribbon you can see stretching across it.
Next, remove the screw near the base of the camera, highlighted in the third image of this step. This is the final fixing that secures the lens assembly in place, so slide it gently out of the back. You have now dismantled the camera far enough to fix it.
Step 6: Fixify Lens
The meeting point of the two cogs is highlighted in the first image below, though I didn't photograph it so well.
If you move the motor to disconnect the cogs from each other as shown in image two, you'll be able to carefully wind the lens barrel in and out. You may need to (carefully!) use a flat bladed screwdriver between two teeth of the large cog to move it at first.
Inspect the cogs to see if there are any flaws, broken teeth, obstructions, etc. In this case, I found the cog on the motor had jumped, and one of the teeth on the barrel cog was slightly worn. The damage was quite superficial, so I used the jewellers screwdriver to scrape it back into a more workable shape and get rid of some chaff that had come off the surfaces.
Do whatever it takes with you own... I'm bloody glad I didn't have to superglue any teeth back in place.
Next, wind the barrel back down, let the motor drop into its natural position and check that the motor cog and the barrel cog are meshing correctly. If so, you're ready to reassemble your camera.
Step 7: Reattach Lens Assembly
Next, reattach the AF/EVF assembly. Again, it should be pretty obvious how this fits, as the camera body has parts moulded to receive it.
Step 8: Reinsert Mainboard, etc.
The hatch that covers the data and PSU sockets on the left hand side of the mainboard isn't secured by a screw; moulded bits of plastic hold it onto the sockets. There is a vacant screw hole (marked, image one) that meets with a part of it, but it's a springy steel plate and almost impossible to screw anything into. There wasn't a fixing there in the one I dismantled, but if there was in yours and you had to remove it to get the mainboard out, I suggest leaving it vacant. The other components of the camera hold the hatch assembly in place securely enough.
Once you get it into place, use your tweezers to lift the ribbons around and over the board. I made a mistake here: The grey wire connector that comes from the AF/EVF assembly needs to be fed under the nearest ribbon rather than over it, as shown below in image two. Also, make good and sure it's not tangled on anything and has a free course to the connector before fixing anything.
Now get ready to slide the upper controls back into place. Again, they have a keyway, and one ribbon socket to connect to, highlighted in images three and four. Use your tweezers to gently push down on the ribbon until it pops into place, then push it into the socket and refasten it with the slider.
Step 9: Awkward Ribbons
The first one connects on the underside of the mainboard. The first three images show how to get it in to place: push down on it gently until it pops into the socket, then push it forwards into it. There is no fastener, it just slides firmly in and out.
The fourth image shows the grey AF/EVF wires fed propery past the casing, ribbon and mainboard. I had to disconnect and reconnect the underside ribbon to do this :) Image five shows the connector plugged back in.
At this point, you should also screw in the two main fixings that sit below the flash unit and the mode dial. The longer of the two screws goes in the right hand hole.
Image six shows all the ribbons back in place. Ready for the last ones?
Step 10: Reconnect Backplate
I found it easiest to connect the power connectors first as shown, then rest the camera lens down to put the ribbons in place. The fasteners on both sockets slide.
Now you can put the backplate in place and prepare to seal the camera back up.
Step 11: Test and Refix Housing
Now, you should have six posi screws and an allen bolt left. Notice that there are two types of posi screw with different threads. I have marked which types of screw go in which holes on the images of the housing below.
Finally, screw in the allen bolt under the flash unit and...