Users cannot access "My Account" page

When any user (including the super user & users with full permissions) tries to access the "My Account" link (user/[uid]), they are automatically redirected to the homepage.

I have trapped the HTTP headers:

GET /user/34 HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-shockwave-flash, */*
Accept-Language: en-us
UA-CPU: x86
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.2; WOW64; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 1.1.4322; .NET CLR 3.0.04506.648; MS-RTC LM 8)
Host: www.mysite.com
Connection: Keep-Alive
[cookies removed]

HTTP/1.1 302 Moved Temporarily
Date: Wed, 11 Nov 2009 06:05:57 GMT
Server: Apache/2.2.3 (CentOS)
X-Powered-By: PHP/5.2.6
Expires: Sun, 19 Nov 1978 05:00:00 GMT
Cache-Control: store, no-cache, must-revalidate, post-check=0, pre-check=0
Last-Modified: Wed, 11 Nov 2009 06:05:57 GMT
Location: http://www.mysite.com/
Content-Length: 0
Connection: close
Content-Type: text/html; charset=utf-8

I have disabled the SecurePages module, so HTTPS redirection is not done. I have configured Apache mod_rewrite logging and there is nothing unusual being logged. I had the devel module configured to trap Redirects and it did not show anything.

I have no idea why the user/ path is being redirected. Does anyone have any ideas what else I can do to investigate and figure this out?

Thanks in advance,
Jason