One can only guess, but it seems as if there was a memory leak in some method in the mdsonar.cpp file used by Analysis Services.
As I was trying to create a cache for a cube, to speed up querying, I ran into the error message listed below:
When I binged the filename mdsonar.cpp, I ony got two (2) hits. Normally this would freak me out a little, but the two links were actually the ones I was looking for, sort of. At least they lead to a plausible solution, unfortunately not an explanation. The solution is to apply the latest Service Pack/Cumulative Update, as listed in KB2660492, for the SQL Server 2008 (not R2) installation I was working on. Regrettably I am not in a position to verify this KB will actually solve this problem, as I am on a tight schedule and out of time. This is really one of those situations where the client would benefit from a little extra effort.
In short I was trying to create a cache of a fairly large set, comprised of several attributes from a couple of dimensions. One dimension has about 850K members and the other has about 45K member. It would seem this was too big a mouthfull, before Service Pack 3 on SQL Server 2008 Analysis Services.