>>Do you know what browser version that user is using? I would suspect it may be browser related issue.
>
>Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)
>

I'm not exactly sure how does it translate, but have you tried to use the exact same environment?

>>Is the site AJAX enabled?
>
>No, I do not use that.

Ok.