diff --git a/plexupdate.sh b/plexupdate.sh
index 90de9fc..dd336a9 100755
--- a/plexupdate.sh
+++ b/plexupdate.sh
@@ -335,6 +335,11 @@ if [ "${CHECKUPDATE}" = "yes" -a "${AUTOUPDATE}" = "no" ]; then
 fi
 
 if [ "${PUBLIC}" = "no" -a -z "$TOKEN" ]; then
+	declare -f getPlexToken > /dev/null
+	if [ $? -ne 0 ]; then
+		error "getPlexToken() function missing, check that it its sourced correctly"
+		exit 3
+	fi
 	if ! getPlexToken; then
 		error "Unable to get Plex token, falling back to public release"
 		PUBLIC="yes"