You may also be Suffering from Buffering. For myself, whenever I'm dealing with any external resource - e.g., a database or a web server - I disable buffering by habit. I find that it prevents a number of arbitrary-seeming and difficult to troubleshoot problems.

#!/usr/bin/perl -w
use strict;
# Ask Perl to pull the chain after every 'write' or 'print'
$|++;

# Rest of code follows
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