It means that FPSC cannot find a component needed due to an incorrectly specified path. In other words - put perhaps more simply - there is a model entity, texture or other media file that is referred to in a script or other associated file which FPSC cannot find in the place it should be perhaps because the name of a file is incorrectly spelled perhaps so that FPSC cannot find the correct file in a location specified. A file named or specified could also have possibly been moved or deleted.
It may mean specifically that an actual path reference itslef is spelled incorrectly - with the same result - FPSC would not be able to find content.
Solution is to find the offending file or reference which could be difficult if you have built extensively since any last occasion you compiled if ever as you will have many files referenced to consider as the culprit.