Well.... I can think of lots of reasons. The most likely is that it's nothing to do with the disk space. When confused, Poser tends to run home, and blame the hard disk space. So if it says out of disk space, and you have some left (and I'm assuming you've made sure that some [at least, say, 10 Meg] is free), then treat it as an unknown error. The best bet is that some file it exepcts is missing, but, like thgeisel said above, you'll need to give more details on what you are doing before anyone can pin it down more than that.