Thanks Jason.
I recreated the users configuration folder and reinstalled design extender. databridge and ecart. and it now works ok
Oops spoke too soon.
Now I get a different error..
When I try to create a new column in the ecart object i get the following...
Javascript error on line 628.
cleared the cache, no change
Got fed up with it, so installed CC, installed all the extensions, get EXACTLY the same error.