svollrat,
I too am using VMWare ESX 5.5u2 with DP 9.02 and I got the exact same thing trying to install that Advanced GRE - it complained about the angular GUI version.
I'm having issues just getting the web plugin registered at all on one of my virtual center servers. I have a case going on that.
I'm also running into problems with the plugin just hanging when I try to access it inside the vCenter Web client. That is the next step.
Ken