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.