This looks like a build problem with pp. Use unzip -l (or winzip on windows) to list out the contents of the PAR "executable". All modules that you need at run time should be there. You need to add explicitly any that are omitted as "-M" options to pp.
This kind of intermiitent stuff looks like a caching problem. At a cost of a slower crank-up time, try running with $ENV{PAR_CLEAN} set to 1.