The second most common problem, a couple ways to fix the errors located in the console window.
Marker System:
If you would like to keep the Marker system, you must delete all 'Editor' folders located in the VRLabs Directories. (VRLabs -> Marker -> Editor)
If you would like to remove the Marker system, you can remove the VRLabs folder. You should also remove Expression Menu options as well as Parameters containing the marker system. Normally for Menu option the Marker will have its own separate section. For removing the Parameters, the Marker systems are all labeled as "M_******"
Other VRLabs Tools will require you to remove the 'Editor' folders as well, in addition there may be other scripts that will give you errors without the editor folders. Simply remove the listed folder(s) from the Console window. (hit clear within the console window, all errors should stay at the top)