Galleryview error in IE

Hey there, the Next / Previous buttons in my Galleryview viewer are not working under IE, if I run the error console in FIreFox I am getting this error

Error: e. is not defined

if (e.button != 0) return true;

The viewer is working in FireFox, Safari, and Chrome, just a problem in IE7 and 8.

Any ideas?

Thx.
Marc Musial