I saw a few very old posts where this happened but no results. I have used 5.5 for a year or more with no issues. Today all of a sudden when I need to put a file on my server, DW closes abrubtly as soon as I click the button with no warning. I have tried rebooting my machine and no updates or changes have taken place since the last time I used it only hours before.
I seemed to fix it.
I tried an old trick I've used in the past where I change my workspace to another view and then back. I guess this sort of resets your workspace and shakes out the dust or something. Anyway, maybe this tip will help someone else.