When you export libraries you also need to make sure that you don't use any mapped drive and use absolute path like \\<sharename>\<folderonshare>\<libraryfilename> else performance center won't find the files.
One thing you can check for proper path that should be accessible from performance center is location set in a GUID named file under libraries script folder. Go to your <script>\libraries folder and open GUID named file with notepad. Look for location under the tag <truLibraryRef> in that xml file, this path should be accessible in performance center.
Thanks!