uninitialized value in concatenation?

[David Humpherys]

when i run a script that has the following bit of code I get an warning:
use of uninitialized value in concatenation (.) at....
I get it for the line:  if (($sth_display->{NAME}->[$c]) !~ /id/i)


Is my syntax correct here.?  The program runs (occasionally) and i get
appropriate results...I just want to get rid of my warnings.


        &ConnectDB;
        $sth_display = $dbh->prepare_cached("$mystatement") || print "Can't prepare
statement.\n";
        $sth_display->execute;

        for ($c=0; $c < $sth_display->{NUM_OF_FIELDS}; $c++){
                if (($sth_display->{NAME}->[$c]) !~ /id/i) { #if it isn't an id_field
                        print <<"HERE";
                        <td>$sth_display->{NAME}->[$c]</td>
HERE
                }
        }


thanks
david