BuddyPress – 404 page error in IE, FireFox is Fine

Hi,
I have a problem with 404 pages and IE8 when creating a group or forum post.
The problem is only with IE, FireFox works as expected with no errors.

buddypress.1.1.3
wordpress mu 2.8.6
wpmu bp magazine 1.0.2
Windows Vista and IE8

Logged in as Admin I get the 404 on the following URL.
http://taggeriffic.com/members/admin/groups/create/

I have tried the default theme, no plugins enabled apart from buddypress and the error pages were shown.

The problem is only with the Windows Default IE browser, I have IE8 and IE7 on different machines, and with FireFox it is working just fine, and I can create groups and forum posts, so it opens up thinking around the Browser, but over 75% of browsers are IE, so I really need a solution.

If you have an IE Browser feel free to test the error, just use the View > Random xxxx top left of screen.

http://www.taggeriffic.com

Or try creating a group,
usr: test
pwd: test2010

I have posted this as a BP support ticket, the BuddyPress forum did not post the topic.

In FireFox it is running a function to return the page, this takes about half a second, in IE it seems to error before the page loads.

Thanks in advance

David