There were no errors raised during installation?
And there are no errors raised when you do a build?
You might want to double check your settings in Visual Studio in the Configuration Manager for the project/solution to see that there are no special post build steps or anything that is mucking this up.
If not that's pretty strange. I'm not sure I can think of anything except to try reinstalling either XMetaL Developer or both Visual Studio and XMetaL Developer.
If you can provide more information (ie -- what's listed here regarding OS, service packs, product version, etc:
http://forums.xmetal.com/index.php/topic,384.0.html) some part of your configuration might stick out as being the trigger.