1) Found this: Increase your virtual memory
1) Right-click on the My Computer icon and select Properties.
2) Click on the Performance tab and click the Virtual Memory button.
3) Select Let me specify my own virtual memory settings and increase it or select System managed size.
2) Hm. Seems like you have a corrupted file. Maybe someone here could be so nice, search his "railgun.bsp", upload and post it here, so zimmy could replace his by this one????
Hope it helps