I take it you're running this on Vista?
This is because windows can't find the manifest file for guitest.dll
created when the link step is done.
If you look in the build tree, you'll find guitest.dll.manifest. The
short term fix is to copy that file to either the root of the build tree
or the t directory where the test scripts reside.
The long term fix is to modify the make file to embed the manifest file
inside the DLL.
Here's a link to an msdn blog discussing the problem:
This is msdn article I used to modify the make file for embedding the
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