DTD downloads breaking on anything

Hello,

A few hours ago I noticed that any request for DTDs to your site (for  
example: http://www.w3.org/TR/xhtml1/DTD/xhtml-special.ent) began to  
break on any request with MSIE in the useragent.

For example:
Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0;  
SLCC2; .NET CLR 2.0.50727; .NET CLR

Will return a 403 but:
Mozilla/4.0 (compatible; MSE 8.0; Windows NT 6.1; WOW64; Trident/4.0;  
SLCC2; .NET CLR 2.0.50727; .NET CLR
(I just removed the “I” from MSIE) works fine.

This also happens to break any request made from the .NET framework as  
it uses a useragent with MSIE in it.  I don’t really know who to  
direct this to but I imagine it’s a pretty large issue.

Thanks.
Steve