Hhhm it could be created from XMG after the fact as some temp file because its not in the default installation files that I can see. I just tried WinSCp to copy and/or open it but I cant even do that:
Error code: 3
Error message from server: Permission denied"
Any suggestions on how to backup the files directory than so that it ignored that file? I try to backup the DB and files to one place(using the below line) but have to do it the long way because of that file.
tar -cf - /backup.sql /forum/ | gzip -c > /backup.tar.gz
All files and directories in internal_data should be writable. Some sort of server configuration you have seems to be making files not writable. Deal with that and they should be writable and deletable.
I'm not doing anything special to put any temp files there.