This Code=007 error is far too common to my liking.
The scenario you are describing is making me think it may be a problem with your gw.dat file. I have had this very same problem quite a few times.
I maintain several copies of my gw.dat to make sure I can replace it when needed.
Basically it appears to me like ANet store some game caching information in the gw.dat file as you play, which can get corrupted if your connection is unstable / laggy or if you switch between several different network connections, like ethernet, wifi, mobile, etc. while keeping your pc online.
I would suggest trying to reinstall GW on your pc (not uninstall, just a reinstall, it will do a replace of you gwsetup file and the GW launcher, gw.exe).
If this doesn't work, replace your gw.dat file with another recent copy or simply delete it out of the directory and the content will be downloaded again when you launch the game.
BEWARE THIS DELETION / DOWNLOAD OF THE GW.DAT - this uses your bandwidth cap, so only do it if you have a high / available cap.
You can download all the content in one shot by doing gw.exe -image in a command prompt in the GW directory. You cannot play the game while this download is taking place and it can take a while if you have a slow connection. There are literally 10's of 1000's of files that will be downloaded if doing it from scratch, coming to about 1.5GB-2Gb of data for all 3 chapters and expansion in a compressed form.