Relative Path not being identified in WiXSetup Project

[sansa20]

I have replaced all the hardcoded path for my installer binaries using relative paths as such "......\Prerequisites\Blah.dll". Weirdly some of the binaries work, but others show the error - The system cannot find the file '......\Prerequisites\Blah.dll' with type ".
I am unable figure out the issue because the path to all the binaries are in similar folders, and some of them do work...