Hi Wisk,
I noticed that your graphics card and RAM are both under our minimum recommended specs. While this error may no longer be occurring, it might be beneficial to upgrade to at least a GT 450 or higher and 8 gigs of RAM to reduce the amount of performance issues you may experience in the future. Axtel your pc seems above this specification, what do you have in your level? Does adding any particular asset or blueprint seem to cause this to occur?