As suggested by eyepopslikeamosquito above, consider using the full path to the ComLine.pl program: 
exec( '/path/to/ComLine.pl', @args ) or die "exec: $!"

[download]
or invoke the Perl interpreter ($^X, documented in perlvar), also suggested above.

--sacked

In reply to Re^2: Exec() argument format by sacked
in thread Exec() argument format by MonkPaul

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