Some possibilities: do you have a full disk? If not, can you write to /tmp? When man processes a page, it sends some temporary stuff to /tmp, so that may explain it.
After rebooting, everything seems to be working normal again. I have over 2.5 G of drive space, so that should not be the issue. I think it has something to do with Microshaft Office. I'm running vX and have been getting weird errors from word saying things are wrong with my drive and shuts off Autosave then crashes. I think these items may be related. When I run Drive 10 though, nothing is wrong with my drive. I don't know what is going on, I'll try to do some more digging around the next time it happens.