You probably have no more in memory. Open the amount you need in memory (you will need to use the service key). Use the dealer programming manual to print out the SRV files.
If you don't have the dealer manual, one of the users has it here:
http://the-checkout-tech.com/manuals/cashregisters/Sharp_ER-A410_and_ER-A420_programming_manual.html
Registerman
August 2013