That file contains user defined calculated PIDs. It won't cause any problems if it is empty. However, the reason that it is missing might cause other problems.
EFILive stores the names of the folders in which all the configuration files are stored in the registry here:
\\HKEY_CURRENT_USER\Software\EFILive\V7.5\Properti es\Dir
You may need to manually change those folder names to match where the files were actually installed (My Documents\EFILive\V7,5\...).
Regards
Paul