I had this issue but it was rectified by using the -maxmem=512 startup parameter.
I also found this cleared up a number of texture problems and all my crashes to desktop.
It limits the amount of RAM arma will use so it may impact performance a bit, but i've found it now provides a more stable experience.
There's a post on this issue on the bugtracker site:
http://bugs.armed-assault.net/view.php?id=2091