the fact is that grsecurity is supported on exactly one kernel version: vanilla from kernel.org.
This does not surprise me. What does surprise me, though, is that Mandrake would make
anything a key part of their security model, and yet not provide any configuration utilities or even information on it...
More surprising has been the fact that it is so difficult to find help; typically, if I type the text of an error message into Google, I can find many sites that have answers to my problem. In this case, it took visits to several dozen sites to find out that "grsec" refered to "grsecurity", and a few more sites to get a link to this site.
And, for the record, it has now been 12 days since I posted my problem on mandrakeexpert.com, and it still has not been "reviewed by an expert"!