I used "nedi-2.2C.zip" to do a fresh install. When creating a new SNMP (not yet existing) definition in Other-Defed.php, the screen will be empty.
This is caused by a typo on line 489.
if( isse($src) ){
"isse" should be "isset":
if( isset($src) ){
After correcting this, everything works fine.
Thanks