If you're fetching into an array, use fetchrow_array.

$sqlStr = "select createwbparserun('$directory','$filename')";
print "$sqlStr\n";

my $sth = $db_in->prepare($sqlStr);
$sth->execute();

if (my @aRow = $sth->fetchrow_array)
{
  print Dumper \@aRow;
  $wb_runkey = $aRow[0];
  print "WORKBOOK run key: " . $wb_runkey . "\n";
}
[download]

A similar example using fetchrow_arrayref would be:

#... same preamble as before ...

if (my $aRow = $sth->fetchrow_arrayref)
{
  print Dumper $aRow;
  $wb_runkey = $aRow->[0];
  print "WORKBOOK run key: " . $wb_runkey . "\n";
}
[download]