Thank you for your post and file.
This appears FileMaker is trying to uncompress a file/image/PDF. What can you tell me about the file? I also see there are references to fonts not being found (F_2, F_3, F_4, F_5).
What are the clients doing at the time of these entries?
I talked with my customer's admin - but this is not to find out, because nobody notices when this process starts.
We have up to 20 clients in several locations ... no way to find out which client-action triggers this. Sorry.
But there is one hint: This customer had often server-shutdowns with FM-Server 13, when many PDF's have been postet in a short time. Since FM-Server we don't have this problem anymore - but now we have the Stderr.log-problem, about once a week or once in two weeks.