I've been playing around with Team Test 2008 running on Windows 7.
When I try and capture a web test, the browser would lock up with the comment:
"The web test recorder must be launched from within Visual Studio".
WTF, I am within Visual Studio!
Mr. Google to the rescue and the solution is that you have to run VS with administrator rights.
Right-click on the shortcut / Properties / Compatibility / Check "Run this program as an administrator".