Program stops mid file

Let me start by saying that the WINCNC guys are great and have been super helpful getting my new-to-me router running right.

I have a new problem and wanted to check here before I bother them more. A problem developed recently where the router will stop mid-program. These are programs that we have run before and have run since without any problems. Once was right after a tool change, and once was in the middle of a cut. The machine just stops dead in its tracks and the spindle keeps running.

We are using the router more as we get it worked into our production, and I wonder if it is just running out of memory? It is a 2008 CNTMotion running on an old version of windows (XP maybe)?

If anyone has run into this or has any ideas, I would appreciate it.

Thank you,
Blaine