PowerPoint 2007 add-in issues

Created a PowerPoint 2007 Add-in for a client to add buttons in the ribbon to paste in excel objects and also to break the linked objects.
But it didn't run on my tst pc!
After some muckign around, found these worked fine in the addins directory.
So was it hte d: drive area that was causing issues?
Tried d:\temp and it worked. But the d:\!Clients didn't.
They all were in trusted locations so the only difference was the exclamation in the file name.
Why would this cause issues?
Another case of finding a workaround for some Microsoft Office Product.
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Tom Bizannes is a Microsoft Developer who can talk the language of Business Users.
He works best with a good cup of coffee.