Or you aren't updating your OS when Microsoft releases new updates (otherwise I think your machine could have not installed that patch/hotfix), or the problem could be that VPN software isn't compatible with Windows 8/8.1:
It seems you got a stop error code 0x0000001E (KMODE_EXCEPTION_NOT_HANDLED) BugCheck 1E, {ffffffffc0000005, fffff802dced460c, 0, ffffffffffffffff} Probably caused by : athw8x.sys EXCEPTION_CODE: (NTSTATUS) 0xc0000005 - The instruction at 0x%08lx referenced memory at 0x%08lx. The memory could not be %s. athw8x.sys --> Qualcomm Atheros Extensible Wireless LAN device driver - Driver for Qualcomm Atheros CB42/CB43/MB42/MB43 Network Adapter - Qualcomm Atheros Communications, Inc.