Pro can't enable 'author intro' tick box Answered

It's not as if I've got anything interesting to say, but when I tick the 'author intro' & click save settings, nuttin' happens.

Error in page says:

Line:484
Char: 3
Error: 'feedBack' is undefined
Code:0
URL: https://www.instructables.com/you/customize

I'm using IE 6 SP2 on winXP.