opendkim configuration not loading properly

From Ubuntu Community Wiki, OpenDKIM uses two files for configuration:

• /etc/default/opendkim: It control how opendkim binary parameter. See the man page here. Two important parameter for this file DAEMON_OPTS and SOCKET. See man 8 opendkim
• /etc/opendkim.conf: The main configuration file read by opendkim binary when it runs. See man 5 opendkim.conf

The content of your /etc/default/opendkim file abvoe should be placed in /etc/opendkim.conf. You should only configure socket and additional binary arguments in /etc/default/opendkim.

FYI, the error message above Line-X not found was threw by /etc/init.d/opendkim, especially this line

. /etc/default/opendkim

Space-after-dot syntax was shortcut for source in shell. Your /etc/default/opendkim wasn't valid shell script for assigning variable. So, the init script try to execute but it fails because it can't found the binary.