I've tried saving as DAT and TXT but nether are working I've even tried using the in app tutorial examples but the tutorial keeps getting the same error

you probably didn't format the number right. otherwise, i think you're either changing the example wrong, or looking at the wrong example. formatting help: -DAT Put it in an array and save with SAVE "DAT:NUM",ARR -TXT Convert it to a string with STR$() and save with SAVE "TXT:NUM",STR

Here is a load/save sample I made a while back, hope it helps.

Thanks for the help it was STR that was missing