I'm not sure but AFAIK on some OSes you should release locks creates with flock before closing filehandle. That is add

flock(tempfile, 4);
flock(logfile, 4);
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before closing these filehandles.

P.S. You should avoid using numbers for constants as it is hard to read and is not fail proof. Use symbol names. use Fcntl ':flock' defines for you LOCK_SH, LOCK_EX, LOCK_UN and LOCK_NB constants.

--
Ilya Martynov (http://martynov.org/)