I only have a 52259, so cannot verify it with a 52255. I'm using CW for MCU10.6, and here it creates the cfg and mem file for me.
I think you cannot use the 52259 files for your 52255, because the memory does not match.
So don't use the wrong files, use the ones inside/from the project:

Just in case, I have my project attached so you can take it from there too.
I hope this helps,
Erich