Hello,
... just an additional short note.
If you use "web-enabled" forms with "Forms Server" you have to keep in mind that the worker process (ASPNet_wp.exe) runs with a weak account (by default) which don't have permission to interact with desktop.
Please have a look at the following KB article by Microsoft for a solution...
http://support.microsoft.com/kb/555134/en-us
Regards,