Comment 11 for bug 828682

I got the same problem.
This also seems to affect only certain special characters.
I typed my password differently to see what causes the problem:

^_b7*!:;@ is fine for example
while
^_b7*!:;@ç isn't
but
^_b7*!:;@a work !

So I guess xscreensaver has a problem with combinations of special characters, surely a layout problem.

My laptop is an Asus x72j serie and I'm using a fresh install of Xubuntu 11.10.
I hope it will be fixed soon.