Game crashing when I change blocks

[Achelousaurus]

For a few months now I keep getting this.
I rarely get 630 but like once a day I crash when I change block or go to my room.

My PC hasn't changed for well over a year and 2-3 months ago I completely uninstalled the game (even deleted the registry entries) and re-installed it but that didn't change anything either.

I use the tweaker but not the proxy. I use English patch, Large Files, Story patch and item patch.
Oh and I am on Windows 7 Home premium

Any idea what could cause this / how I can fix it?

[Variant]

Could you try without the item patch?