That will teach you to not put passwords on your PLC programs. Don't use them unless you have a really good reason for using one.
Passwords are for situations where the programmer needs to protect intellectual property or prevent changes to the program for safety, warranty, or liability reasons. As such they are not easy to circumvent. And for the most part since we have no way of verifying if a user's claims are true or not, or if the user it trying to hack someone else's IP, we don't offer much help in the way of password cracks. For some PLCs there isn't an option except to clear the memory or have the PLC manufacturer clear the memory.