J-BusinessDirectory - Blank screen at edit categories

I have just installed J-BusinessDirectory and am a new user to it.  I'm using Joomla 3.4.0 and J-BusinessDirectory 4.1.1.

When I try to edit categories I only get a blank page.  I've tried searching the forum here and for some reason can only see the original posts and none of the suggestions or replies. 

Any help would be great!  Thank you!

Edit:  If I try to edit a Business Listing, Order, Review, Offer, Events, Event Types, Reports or Package or I try to add a custom attribute it just sits there and doesn't do anything.

Hi,

If the problem continues please disable the system plugins one by one to see which one is causing the problem

 I have the same or similar problem  I just installed a clean 4.2.1RC install on joomla 3.4.1 and I get a blank sceen for any of the backend j-directory admin links though. Useless for the moment. Please help :)

J

Hi,

The solution is the one presented above.
We have included again bellow.

If the problem continues please disable the system plugins one by one to see which one is causing the problem