That fixed it! You've saved me many hours of work in re-implementing the IPC to avoid using that module, which also would have lost STDERR monitoring. Thank you very much.
Edit:
Looks like that solved the compiling problem, and works great for the isolated example, but introduced a nasty memory leak in my actual script... 115 GB used in about 30 seconds before it failed by running out of memory. I suspect that might have been what messed up Perl2Exe since it basically kept relaunching my app like I'd put a while(1) loop around my code. I'll have to investigate further, the launcher component is purposefully kept as simple as possible and just handles launching and coordination. I appreciate your help as I didn't really know where to even start to fix that problem since I had no idea how the PAR environment differed from the standard PERL environment.