This just popped up after hours of playing. The bar area loads fine, but as soon as I get near the southern duty checkpoint, or near any buildings for that matter, I get a CTD. I looked through the log file and this might be the apparent cause:
stack trace:
001B:00458BDE XR_3DA.exe, CKinematics::LL_SetBoneVisible()
more info:
XR_3DA.exe caused ACCESS_VIOLATION in module "E:\THQ\S.T.A.L.K.E.R. - Shadow of Chernobyl\bin\XR_3DA.exe" at 001B:00458BDE, CKinematics::LL_SetBoneVisible()+222 byte(s)
System Error:
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0x00000012 - There are no more files.