I have had this too before, but then have also found that sometime the same happens when using the built in Dreamweaver wizzards also.
One thing that I did was delete the wincache file (which is all over this forum), but also looked at connection issues that DW has with some servers.
I can't remember the steps that I went through, but it included either adding or removing www. on the testing server settings etc.
These things helped a little, but I stiill get it happening a few times.