Scenario #1: According to the manual, 4 red lights flashing, in addition to the error light on the front of the unit flashing (5 lights total), means “The voltage is abnormally low.” Putting a fresh battery in should take care of the problem.
Scenario #2: If the error light on the front of the unit is solid, and the 4 lights on top are flashing, the manual says “After an internal error occurred, copying and formatting is not possible.” You’ll need to contact the place you purchased your unit from and hopefully they’ll be able to replace or repair it.
Good Luck!