You can. The following runs on my ActiveState Perl 5.6 system:

use strict;
my @myrowidarray;
$myrowidarray[0] = 100;
my $myint = 0;

if ($myrowidarray[$myint] ne "del" && $myrowidarray[$myint] ne "cal" &
+& 

$myrowidarray[$myint] ne "foo") {

    print $myrowidarray[$myint];
}
[download]

I think the problem might be that you have a right parenthesis after your initial set of conditions, and then your additional condition has yet another right parenthesis.