Locking up on X/Z report (TE4500F) - Memory issue?

Hi All,
I bought a second hand TE4500F and have downloaded CV22 to program it. However, I seem to have a problem that when I try to do an X or Z report it will lock up (it starts to print stuff out, but just hangs). The only way to recover is to do a reset (hold receipt and power-on).

I think it's related to the number of PLU's I've transacted. To narrow down the problem, I've done a complete reset (hold journal down while powering on, entered code 10830, 000), and manually programmed some dummy prices into some PLUs. If I now do a few transactions (10 or so) comprising of multiple PLU presses (say about 25 each) i.e. totaling about 250 PLU sales, the machine will lock up when doing a X/Z PLU report.

I first noticed the problem after I had programmed up the machine using CV22, and it would lock up after only about 100 PLU sales!!! This leads me to believe it's a memory issue i.e. obviously when I've programmed all the clerks,depts, PLUs, etc there's less memory to store all the PLUs sales than when I've started from "fresh".

Do I need to either physically increase its memory (either increase the standard 512k RAM, or add a CF card)? I can't believe the standard machine only allows a few hundred PLU sales before locking up!?! Or do I need to allocate some more memory using CV22? If so, which File Name should I increase in the memory allocation table? From memory, I think I've allocated about 180k for my setup - surely this leaves enough of the 512k for storing the PLU sales? Or is that the problem - should I be adjusting one of the file names so my allocated memory is nearer the 512k mark?

Many thanks,
Chris.