The 'out of memory' message probably refers to your PC's available memory during compilation. PBP does not take advantage of all your PC's available RAM, whilst PBPW does.

There is no 'other' PBP (by 'other' I mean another version you have to purchase)... it's just down to the way you invoke it...

A standard example:-

PBP -p16F876A myprog -v

A large memory example:-

PBPW -p16F876A myprog -v

Actually where you run out of memory is probably dependent on your PC... on mine it happens somewhere between a 4k and 6k compilation. You might as well just run PBPW for everything and not have to worry about it again.