Mercurial stops working after setting up a Build Step

Hello,

i started to set up Teamcity for our Company to get CI working as we desperately need it.
So i watched some tutorials how to configure mercurial with Teamcity.

I set up a completely new Win 2003 Server and installed TortoiseHg first. Then i installed Teamcity and followed the Admin startup in the browser. I created a Project with a new VCS which used Mercurial. As soon as i entered the appropriate data in the fields and hit save, then edit the vcs again and hit "Test Connection" a popup came up and it said that the Test was successful.  After setting up a Build Step the VCS didn't work, either i had to type in the password for tortoiseplink myself OR when i hit "Test Connection" after setting up a build step it would check forever and never give me a popup with an answer if the test failed or was successful.

Could you please tell me what i am doing wrong? Or what could it be that the "test connection" works before i set up a build step and after setting up the build step it doesn't?

I appreciate every help you can give me.

Greets

kazoooka