Some of their prior responses to this problem suggested it was bad memory on a server or not enough memory. It's a problem that I've seen since January (my first use of Auctiva).
I'll take my own guess and suggest checking for application "memory leak", i.e. app(s) or system using but not properly releasing memory. That will typically push you to a paging freezing just before you it the depletion WALL. Need one of those banging head on wall graemlins (HERE).
Dan