I keep running into this error in my Magento backend.
I changed some categories and soon after that I ran into this error:
Fatal error: Call to a member function getId() on a non-object in /home/test1039/domains/sambalshop.portalserver.nl/public_html/lib/Varien/Data/Tree/Dbp.php on line 331
I only see the error on the categories page. The rest of my Magento environment works fine.