MS WORD2K ERROR FROM NT FILE SERVER

Office has multiple users accessing Word2000 from NT server – 5 win982e machines and one win95 unit. All users receive error when part way thru any doc that says MS Word file you are using does not exist, and you are almost out of memory. The mouse and cursor are then unusable until you ctrl-alt-del and end the Word task. This error was also received by a single user on the system on Saturday.