I found a similar problem, but have also found a solution. Given my programming roots, I was careful to check the errors and noticed that all of the Plug-ins that couldn't be found were supposed to be in the "Plug-ins" folder (note the lower-case 'i'). VW 11.0.1's Plug-Ins folder had an uppercase 'i'. Simply navigate to your VectorWorks folder (/Applications/VectorWorks/ in OS X) and change the name of the folder from "Plug-Ins" to "Plug-ins" (upper- to lower-case 'i'). Quit VectorWorks and relaunch. This should fix your problem...
I agree that this should have been caught in the testing phase, but, hey, at least it has an easy solution...
