use strict;
#use warnings;
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That should be:

use strict;
use warnings;
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while (<COMPFILE>) {
    $comptn = substr $_, 0,10;
    search_tn($comptn);
}


sub search_tn {
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That should probably be:

while (<COMPFILE>) {
    search_tn( substr $_, 0, 10 );
}


sub search_tn {
    my $comptn = shift;
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        next until $. > 1;
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There is no need for a loop there!

        next if $. == 1;
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        if ($record[0] eq "TLR") {
        } else {
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Better as:

        next if $record[0] eq "TLR";
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                if ($error == "") {
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You are using a numerical comparison on a string which will not work correctly.

                if ($error eq "") {
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