in reply to Bad file descriptor

Further investigation reveals that the following line fails in Harness.pm $fh->open($cmd) or print "can't run $test. $!\n";

Actually, that line works perfectly :-)
It prints the errormessage, doesn't it? The problem is in your code, but without knowing what's in createnew.t we can only guess

Please post (relevant) code which produces the behavour

Paul