After some investigation, our technology have discovered, that the bug was caused by code in antirootkit module, which is linked into aswsp.sys driver. When VPS update was released yesterday, it started querying some additional PE information data from driver which crash OS.
We haven't seen any crashes on Win7 x64, or Win8, which supports our theory that the main cause is probably Win7 x86 OS bug. It is also worth mentioning, that crashes are not inside our driver, but in NT kernel module.
Sorry for any inconvenience caused.
Alex