init script issue: unexpected then, expecting } - linux

Question

I have an init script (im running Debian) to start serviio a DLNA server. When i go to start the service i get the following error. Any help would be appreciated. Please note: I'm VERY new to linux/bash/debian.
I get this error: Invalid Syntax: unexpected then on line 43, expected }
With this code:
#! /bin/sh
#
# /etc/init.d/serviio
#
#
### BEGIN INIT INFO
# Provides: serviio
# Required-Start: $network
# Required-Stop: $network
# Default-Start: 3 5
# Default-Stop: 0 1 2 6
# Description: Start the serviio DLNA server in headless mode
### END INIT INFO
SERVIIO_HOME="/opt/serviio"
SERVIIO_DAEMON="serviio.sh"
SERVIIO_BIN="$SERVIIO_HOME/bin/$SERVIIO_DAEMON"
SERVIIO_USER="serviio"
# Source function library.
. /lib/lsb/init-functions
RETVAL=0
check() {
# Check that we're a privileged user
[ $(id -u) = 0 ] || exit 4
# Check if SERVIIO_HOME exists
test -d "$SERVIIO_HOME" || exit 5
# Check if SERVIIO_BIN is executable
test -x "$SERVIIO_BIN" || exit 5
}
start() {
check
echo -n "Starting Serviio DLNA server: "
/usr/bin/sudo -u $SERVIIO_USER -H $SERVIIO_BIN -headless &
RETVAL=$?
if [ $RETVAL -eq 0 ]; then
touch /var/lock/serviio
log_end_msg 0
else
log_end_msg 1
fi
echo
return $RETVAL
}
stop() {
check
echo -n "Shutting down Serviio DLNA daemon: "
killproc "$SERVIIO_BIN"
RETVAL=$?
[ $RETVAL -eq 0 ] && rm -f /var/lock/serviio
echo
return $RETVAL
}
restart() {
stop
start
}
case "$1" in
start)
start
;;
stop)
stop
;;
force-reload)
restart
;;
restart)
restart
;;
condrestart)
if [ -f /var/lock/serviio ]; then
restart
fi
;;
status)
status serviio.sh
;;
*)
echo $"Usage: $0 {start|stop|status|restart|condrestart|force-reload}"
RETVAL=2
esac
exit $RETVAL

Answer 1

I can run this script without getting syntax errors,, but I don't have serviio installed. Anyway, my guess would be that $RETVAL is somehow empty, and that it needs to be in quotes:
if [ "$RETVAL" -eq 0 ]; then
Although I would think that would complain about '[' expecting a unary operator.
The next thing to try would be to comment out sections at a time by prepending "#" to the lines in the section until you can narrow down where the problem is. For example, comment out the whole "start" section, or comment out the "check" function (and make sure you comment out the calls to it, too). That should help narrow it down.