ISAPI Filter not running on Windows 2008 R2 64-bit server

I have developed an ISAPI filter in VS2005 and has cross compiled for 64-bit. I installed it on Windows 2008 R2 64-bit server with IIS 7.5, but it does not work while filter dll loads successfully. I checked it with the following command.

tasklist /m mydll*

Any suggestion/solution why it is not working and how to get it work? Thanks in advance.