Change the || to &&. Your if will always be true with ||. Also, '/bin/sh' and "/bin/sh" are always the same. Read Quote and Quote-like operators in perlop to see when the kind of quote matters.

Update: Apparently I didn't make myself clear since y'all are still discussing the intricacies of Expect. The simple fact is that the logic in your if statement is wrong. Try this:

faulty_logic("fred");
faulty_logic("wilma");
faulty_logic("barney");

sub faulty_logic {
  my $input = shift;
  if (($input ne 'fred') ||
      ($input ne 'barney')) {
    print "IF condition true: input=$input\n";
  }
}
__END__

Output:
IF condition true: input=fred
IF condition true: input=wilma
IF condition true: input=barney
[download]

Think about it.