I've put all sorts of general comments on the code below. I can't find your specific error, but following these style tips should help you find it yourself, or be more likely to get help in the future.

#!/usr/local/bin/perl
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Use perl -w to turn warnings on. Include "use strict;" to enforce variable declaration. See perlstyle for tips.

$hour=<STDIN>;chop($hour);
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There is no real reason to use chop()...get in the habit of using chomp(), and use chop() only when you really mean it.

 #goto LABELEND;
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I realize this has been commented out, but you should not have to use goto. A case can be made for when to use goto, but given perl's great flexibility in flow-control, you can plan to never use it and be fairly safe.

 if (open(NAMEONED,$onedname))
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You should always report error conditions on file opens. Try : open(NAMEONED, $onedname) or die "Can't open $onedname: $!";

 #use PGPLOT;  # Load PGPLOT module
 #print "\nTesting simple point plot...\n\n";
 #print "PGPLOT module version $PGPLOT::VERSION\n\n";
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When posting code and asking for help, remove all useless, commented out lines.

 $k++;goto NEXTLINE;
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This is somewhere where a goto is unnecessary. Look up line labels, next and last in perlman:perlsyn