Yes, btcguild is a separate bug, sorry. BTCguild is the only pool that uses the redirect feature in stratum which was added blindly a long time ago when stratum support was first added and no pool used it. Cgminer's implementation is unfortunately buggy and the only workaround till I can fix it is to connect directly to btcguild's redirected url directly or use a different pool to avoid the crash.
I hope you figure this out quickly

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I thought this was a hardware issue when I first saw this since my drillbit devices were that last thing to show errors before windows tried to close it.
I need's my btcGuild.
Been looking into it. I was unable to reproduce this at all locally so perhaps it's better or perhaps I just don't have the right combo of hashrate and circumstances. I've done some generic changes to make it more robust. There may well be a second issue with btcg related to the frequent restarts it's had lately but I have no firm leads on that.
I'm set for level 16 in load balance mode with about 25Ghashes pointed at it. If you have it right, it shows up after less than 30 minutes. I was trying to watch a flash video when I last noticed my computer getting chunky which eventually led to me trying to fast disable btcguild ,but it was too late and then to get stability back I ended up voluntarily rebooting my system (pc was looking to update my display , network drivers and .net service packs, so I needed to anyway) Picture below is not from most recent event but how I found it after leaving home for a few days not knowing this would happen.
http://i40.tinypic.com/fms7xh.jpgI hope that gives you something to look into and hope it has nothing to do with pm to check winsock headers having problems with compiling.
This reason alone made me give up windoze. Not to mention the frequent restarts because of updates .Set up a raspberry pi changed some of the instructions to compile newest version and been happily hashing since December with no down time. If you don"t like soldering then save some money and skip the lcd.