First, never put execution permission on a .pm!
For the probable cause of your error, have a look at the manual for the "system" function (perldoc -f system):
If you'd like to manually inspect "system"'s failure, you can
check all possible failure modes by inspecting $? like this:
if ($? == -1) {
print "failed to execute: $!\n";
}
elsif ($? & 127) {
printf "child died with signal %d, %s coredump\n",
($? & 127), ($? & 128) ? 'with' : 'without';
}
else {
printf "child exited with value %d\n", $? >> 8;
}