One should adapt the /usr/sbin/dkms script to be more informative when error logging. You can change the line 527 (or similar on your system):
[[ -r $read_conf_file ]] || die 4 $"Could not locate dkms.conf file." \
to something like
[[ -r $read_conf_file ]] || die 4 $"Could not locate $read_conf_file file." \
to see where exactly is the problem located.
One should adapt the /usr/sbin/dkms script to be more informative when error logging. You can change the line 527 (or similar on your system):
[[ -r $read_conf_file ]] || die 4 $"Could not locate dkms.conf file." \
to something like
[[ -r $read_conf_file ]] || die 4 $"Could not locate $read_conf_file file." \
to see where exactly is the problem located.