From TipsOnUsingVbUnit:

VbClassic (old VisualBasic) often gets confused about relative path names when working on projects in more than one directory.
It will add redundant relative paths to all the modules and classes you add.
''(And sometimes, in a fit of confusion, it may add them to all modules and classes in a project.)''
I find that I must always edit the project (.vbp) files by hand before checking into source control, whenever I add classes, modules or forms to a project.

Example:
I'm working on a group of two projects, one in "C:\a\b\c" and the other in the "d" subdirectory, "C:\a\b\c\d".
When I add a class "class.cls" to the project in the "c" directory, the project file (.vbp) will usually show "Class=class; ..\..\a\b\class.cls".
In other words, the relative path says "go up a few directories, go back down through the same directories to the same directory where you started."
Before I check in, I always have to pull up the project files in the "VisualNotepad development environment"
''(or any other text editor ;-)''
and reduce "Class=class; ..\..\a\b\class.cls" to "Class=class; class.cls", which is exactly the same thing -- except that it still works when directories get rearranged.

''It's a minor annoyance.  I shouldn't have to '''hack''' the project file contents, but it's the only way I can get clean portable builds.''

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Keep everything in the same folder if you can. Then there are no relative folders to confuse. -- ThomasEyde