Re: 404 error on BP links
Bummer. IIS isn’t really that common with WP and I think the majority of people here are using Apache based hosts.
You could try what is mentioned at the end of this thread: https://buddypress.org/forums/topic/friendly-http-error-messages-causes-404
The specific error it talks about isn’t what you’re seeing though as I get a 404 on your site with Firefox also.
This link talks about a modified 404 error handler to deal with some of the oddities in IIS handling:
If you do get this working, please post back here and/or in the FAQ topic because it seems there are a lot of IIS users running into similar issues.