What menu items are grayed out? All of them? You should always be able to launch memory and performance profilers, event if no project is loaded.
As of v6, the add-in has moved to %programfiles%\\red gate\\ants profiler visual studio add-in 1\\RedGate.ANTSVsAddin.addin. Sorry for the confusion -- our internal docs are out-of-date.
Also as of v6, the add-in moved out of the performance and memory profiler installers and into the .NET developer bundle installer. But if this is the first time you have used Performance Profiler, this shouldn't be an issue because the evaluation should be the .net bundle installer.
But you can try fixing this as before but changing the add-in location:
regasm /codebase " %programfiles%\\red gate\\ants profiler visual studio add-in 1\\RedGate.ANTSVsAddin.dll"