Oke... i thought i could investigate it some more... by looking at the code from administratorpages from both installations...
And it seems it has something to do with the magic quotes setting.
This is from the 'wrong' site (the part that should do the conditional setting):
\"revert\":\"1\",\"value\":\"Netherlands\"}],\"conditions\":[{\"type\":\"isEqual\",\"trigger\":\"suplier_name\",\"value\"
And this from the working site:
"revert":"1","value":"Netherlands"}],"conditions":[{"type":"isEqual","trigger":"suplier_name","value"
So probably the setting was the culprit. The setting is already solved with a php.ini file in the root to override the setting. But the damage has been done.
So hope someone knows how i can revert it. Is it stored in the database...
But as i type... i think of a way to check it :-)