Anti aliasing

[vieuxchat]

When I put AA on, some weird glitches appears :
some points below the letter "w" and the letter "s", some lines along the screen and, more frustrating, the battles are unplayable because the screen doesn't "refresh" (each frame seems to be dran upon the last one without erasing it, so I've some kind of trails on the whole screen).
I've the last drivers for my geforce 8800 GTX 512, i'm on vista 32-bit (with all the last updates) and a Q6600.

So, I play without AA. But is this bug already known? I already had it on Fantasy Wars, and I hoped that I would get rid of it on EL

Thanks in advance (and for that great games that FW and EL are ^___^)