So are you saying that if you were to print the contents of $dlog2[$co] it would be exactly "*", nothing more, and nothing less? There's not much to trace out here: If your print $fh "  ,"; is failing to print anything to $fh, then the possibilities are:

• $dlog2[$co] doesn't contain exactly the single character "*" and nothing else.
• The $fh filehandle wasn't successfully opened for output.
• You're not actually running the code you posted (either by not running it, by not posting a copy/paste of real code, or by having the entire segment of code you posted here being skipped due to errant control flow.).

You're the only one who can trace out which of those possibilities are the cause.