"Insufficient System Resources Exist to Complete the API"
I have a Toshiba Tecra M4 with 2Gb of RAM. I've had the machine for a while now and every so often, when I went to hibernate I would see a message saying "Insufficient System Resources Exist to Complete the API" (and the machine would only go into standby). On a couple of occasions I've failed to notice this before placing the machine in my bag (and as a result I end up with a hot bag, an even hotter laptop and not much battery left).
After researching this yesterday, it appears that this is a problem with memory fragmentation (a lot of applications running causes memory fragmentation which for some reason prevents the machine/kernel from going into hibernation - this affects laptops with > 1Gb RAM).
Fortunately, this seems to be have been fixed with a post-SP2 patch. (KB909095). You have to contact Microsoft Product Support for the actually patch file, but it is now available - and from what I can tell appears to work well...