Postfix running on SuSe 7.2

I face the problem in my postfix running on SuSE 7.2 Linux Server. It sometimes can't receive some mail and after I upgrade the version from rpm package from SuSE 7.2. More error exist. Please adivce. log file contains following warning message Jun 18 15:59:14 mail postfix/postdrop[22320]: warning: mail_queue_enter: create file maildrop/693113.22320: Permission denied