The new Visual Studio Team System 2008 Team Foundation Server Power Tools, March 2008 edition, may cause 1722 error when installing. There is many possible reasons for that, however one I had can be easily eliminated.

First of all you should get log file. Easiest way is to run command line: msiexec /i tfpt.msi /le log.txt All errors that happened during installation will be logged into the file. If you are lucky enough to have the same problem (if having problems can be a sort of luck), your log file will be like that:

=== Logging started: 23/06/2008 09:06:02 ===

Error 1722.There is a problem with this Windows Installer package. A program run as part of the setup did not finish as expected. Contact your support personnel or package vendor. Action DevEnvSetup, location: C:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE\, command: C:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE\devenv /setup

=== Logging stopped: 23/06/2008 09:06:51 ===

What you have to do now, is to run devenv /setup from command line and wait till finish. To ensure if there were no errors you can run echo %ERRORLEVEL% which should return 0. After that, you can rerun msi and this time install should go without errors. I can't guarantee that trick will do in your case as good as in mine, but it's always worth to try.

HTH