"Could not initiate port: Unsupported operand type…"

My research group was running an EEG experiment about 18 months ago in which we sent triggers to the EEG system through the parallel port. This seemed to work fine at the time. We are currently trying to collect more data for the project, yet now when running the experiment we get consistent warning messages regarding the parallel port, of the form:

Could not initiate port: unsupported operand type(s) for +: 'PParallelInpOut' and 'int'

As a result, our recording software isn’t getting any triggers, which is obviously a problem. To my knowledge, nothing in the code or equipment has changed; but clearly this is wrong, as otherwise it would still be working. Obviously the message implies that, somewhere in the program, an integer is being added to something that is not an integer; but I don’t know where ‘PParallelInpOut’ comes from, that is, what function is using it. Since this problem is unfamiliar to me, I’m wondering if anyone has any experience with such an issue, and might be able to suggest some options for troubleshooting. Thanks in advance!

As an update to this, the warning actually seems to be unrelated to whether the system is receiving triggers or not. Currently (after a hardware fix) the triggers are coming through fine; yet this warning is still appearing on the console every time a trigger is sent by PsychoPy.

Even though it doesn’t seem to be affecting the recording, I’d still like to know why this warning arises, and what I can do to prevent it. If anyone has any ideas, I’d love to hear them.