Update: it's taken a long time, but after individually commenting out lines of code, transferring the result to other computers, And running it there and seeing if it still crashed, I have discovered that this had nothing to do with SFML, so much as trying to get a proper timestamp. Still investigating a fix.
Either way, I think this topic is done with here. Sorry about the original quality; wrote it in a rush on my way to work.
Update 2: Solved. Had to do with allocating to the heap where the stack was more appropriate. Should have paid more attention to those boost tutorials I was c/ping then editing.