Check to make sure that the roll of material is not at the end of the roll and taped to the core. It sounds stupid but I, and many of my customers, have done this multiple times. And yes, even though this error is for the CR direction, the PF direction can affect the CR system.
Other than that: Most commonly, when the error happens right away after turning on the machine it's caused by the head lock mechanism malfunctioning. You can test it by taping the mechanism down and turning the machine on. If everything works fine, you may just need to bend the lock bracket back to a 90 degree angle. Sometime it requires a replacement and sometimes it could also be the solenoid on the head carrriage that is malfunctioning.
Next I would move on to replacing the encoder sensor. If that didn't fix it, it's time for advanced electrical and mechanical troubleshooting.