If it is only one out of several workstations having the problem, it sounds like more of a temp file issue. I'd log out of Timeslips, then search and delete any folders named FulSes*. (Usually, but not always, found in your windows default temp file location.)

Thanks Nancy, but I can't find a FulSes* file on either my desktop or the server. So now it seems to be working fine, but I have no idea why. Here are the steps I took:

Tried to print a particular bill through billing assistant and got the error message.
Exited program and deleted pdoxusrs.net (the other files which were recommended for deletion were not present).
Went back into program and still got error message
Exited and deleted file again. Went into station administrator and diagnosed computer. everything fine.
Back into program and still error message.
Exited to station administrator and it told me to delete those 3 temporary files to fix. Again, only 1 present.
Back into program and error message again. This time, without exiting, I went into a different bill and it printed no problem. Went back to the problem bill and it printed.

I don't know why it wasn't working and I don't know why its working now, but I am happy it's working.

We'll see tomorrow.