I was able to find a workaround by opening a new Workspace and then importing my project from the seemingly locked/corrupted base2 workspace. Not exactly a solution to the problem, but this did bring back WB 3.0 functionality and allow me to retrieve my project files.

Evidently, although perhaps not the best one as I am a novice to WB. As I have Premier Help Service, Wolfram was kind enough to provide a copy to use since WB 2.0 at least sometimes doesn't work with Mathematica 10.0 (at least not on my machine).

In reading online about issues associated with Eclipse sessions this seems to be an Eclipse workspace issue in that the locking files are not being properly unlocked and relocked or are otherwise somehow corrupted in the .metadata directory(ies). Unfortunately, suggestions there concerning deleting the lock file or starting the WB as admistrator do not seem to work (or at least those I have tried so far).