IE8 crashes with theme Social & BuddyPress

Currenty, I am using the theme Social with BuddyPress on a subsite in a Multisite configuration.

Logging into BuddyPress works almost with every browser, however, yesterday at my clients office the website crashed every time after hitting the login button at the homepage. The client is using IE 8 with XP (terrible). The subsite were talking about is leden...

I've granted support access.

Updating IE8 is not an option, since it's part of a network environment in a hospital.