One idea to narrow it down.....can you see (e.g. from header, footer, title
bar of the error message block etc.) which "software" is generating the error
message? E.G. from the VBA/code/custom application written in Access, from
Access/Office or from Windows?

This message sounds so specialized that my first guess is that it's an error
message in the VBA/code/customapplication. If so you might track it down
there.