Hello all, newish forum member needs help!

I have a Hypertherm CNC plasma bed, run by a Burny 3 controller, and using Sheetcam.
I bought the set up second hand, and saw it working prior to purchase. Now i have it set up, i am having problems!

When the controller is switched on, it self checks, then displays 'PGM MEMORY ERR' (Presumably ERR means error). Does anyone know where i should start in resolving this? I know its old technology, but is it terminal, or can it be fixed?

I have a test piece drawn up in solidworks, transfered to Sheetcam, and saved as G code. The controller doesnt seem to want to load the G code, i think the error is stopping the contoller doing anything.
I'm feeling my way around it a bit, so apologies if i am being daft.

Hope someone can help. Thanks, Paul