This sounds like a problem that was mentioned in the old newsgroups. Do the problem machines have Visual Studio 2008 installed on them? If so, the problem is due to the fact that VS installs its own version of the script debugger that does not work so well with TC.
In the post that I saw, the recommended solution was to rename the folder that the VS debugger is in ("C:\Program Files\Common Files\microsoft shared\VS7Debug") and reinstall the old MS Script Debugger. I think that's a pretty poor solution if you still want to work with VS. I also saw some references to the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{78A51822-51F4-11D0-8F20-00805F2CD064}\InprocServer32
It seems that this key can be used to switch between the two debugger versions. It contains the path to a file called "pdm.dll". The old version is usually installed in the Windows\System32 folder, while the VS version is in the path I mentioned earlier. I tried changing this for the first time yesterday, and it does seem to work OK.
Also, while I still had the VS version active, I found that debugging in TC was very slow after I had used VS. If I hadn't used VS since rebooting, then TC debugging was not slow, but it did have the problems mentioned in the first post of this thread.
