What'd probably happened is that when the .NET runtime loaded the ProfilerCore dll into the w3wp process, it crashed on the call that initializes the profiling session. This could have happened for virtually any reason under the sun, but like with all things Windows I would have a look at permissions. If your app pool runs as a certain user, try matching the ANTS Memory|Performance profiler service to that user so the app pool doesn't start as SYSTEM, which would be the default.
The first error message is pretty meaningless and always occurs when you try to run w3wp.exe in debug mode like ANTS Profiler does. Anyway, the fact that ASP .NET will not be doing any process recycling is a good thing in my book!