This was a known problem with Word 2002, (I think), in our PC's at work. We used to have to check our temp folders every so often and clear out all of the temporary word files. Our PC's were not networked then, so each individual PC had a temp file with hundreds of tmp files if the users didn't check.
We never did track the problem down, but perhaps it is in the Options of Microsoft Word.
If you goto Tools > Options and click the Save tab, is the option to "Allow background saves" ticked? If so, that may be the problem.
This option works well if you are editing an already saved document. It re-saves regularly over the original.
But if you create a new document and haven't saved it yet, when this option is called up it has nowhere (and no name) to save the document to, so perhaps it creates a tmp file in the temp folder.
This must be a different option to the "Save Auto recovery info every .... (mins)" option. That one is called if the computer crashes, or Word fails in the middle of a document. The next time Word is opened, it will give you the option to recover the lost document up to the time it was last saved.
So, perhaps there is a link there. Word saves in the background to a tmp file, then if Word or the PC crashes befoe the document is saved properly by you, Auto Recover can recover it from the tmp file.
You can turn off background saves, and see if this cures the problem. But if I am right, (and I never thought of this before), Auto Recover may not be able to recover a document on a program or system failure if this option is turned off.
I have XP SP2 and Word 2003 with 320 mb RAM (ok, it's not a lot of RAM). Word keeps a long list of ~WRD and ~WRL TMP files even after I've done a disk cleanup. Is there a way to stop Word from holding on to them?