Issues with IIS7 after enabling FastCGI

[jaijavan]

Hello,
I was using Mantis [1.2.0 Release Candidate 1] successfully for past 1 year with no issues. My server is Windows 2008 with IIS7 and MYSQL 5.x
Recently, I had to install fast CGI and ISAPI Rewrite to enable clean URLs for Drupal. All my PHP based software [5 other sites] were fine after this change.
However, mantis started going in a loop. For example, if I access Mantis as localhost/mantis/index.php, it goes into an loop by requesting same file again and appending the path. So, I end up with requests like /localhost/mantis/localhost/mantis/localhost/mantis......... This looping doesn't stop unless I force it.
BTW, I have tried to stop this by creating a web.config file that works with other PHP-MYSQL applications. But, no luck.
Can someone please help me out here?
Thanks.
- Jai