I have re-checked permissions and there is no difference between the folder which is mentioned in the error and any of its parents.
I wondered if it could be the file path length, the path ‘/mnt/documents/30-39_Hacking/32_Hacking_Projects/32.14_X230/roms’ is 64 bytes long, which would overflow a 64 byte buffer with a trailing NULL, but there are many longer file paths. I maybe guessing incorrectly here, but I can’t really think of anything else.
I don’t have a spare machine to try running the BSD executable outside a jail.
Anybody have any other suggestions that I can try to narrow down this problem?