I suppose custom location…a problem that we encoutered too…maybe you should update the docs for arbitrary locations and say that one has to install vray at least once into the correct maya location and “rip out” the 3 modified mel scripts from ../maya/scripts/others and put them somewhere on the network…
The changes to the scripts are not fatal in any way; the commonTabColumn error doesn’t have any bad consequences. In an ideal world, we wouldn’t have to modify those scripts, and I hope that we won’t have to in a future Maya version.