I tried that "if used - use in" trick right before the cursor is created and it STILL dies after going through 3/4 of the process cleanly.

I ended up splitting the process into 3 pieces. Luckily, the results are set up so I can just add the 3 pieces together at the end. I have to reconfigure the program for each run. Shutting down the program and restarting it seems to make it release whatever it has been holding onto, which makes me think it is a memory or temporary files issue. Any other ideas or suggestions?