DLL search path depends on how the lib have been build
but under windows it might be possible to put a DLL needed by another binary (dll or exe) just next to the second
so you might try to run pd with verbose option, then switch to debug log level.
Then when you load Gem, you should see in the Pd's console which plugins gem is loading.
If it fails because of a missing dll, it should tell you which one.
Then you have to find the exact version of that DLL and try to put it next the gem_filmQuicktime.dll file (somewhere in the Gem binary folder).
This technique is kind a hack and might lead to crash but it's worth a try.
If you can't install anything easily on the machine then it could help.
One last thing, if you have a working installation, you could try to look what dll gem_filmQuickTime.dll need and where it find it with some tool like dependency walker.
good luck
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