Can not run walktut in cel

Hi, i am new in cel. When I run the walktut in cel, it said that "Could not open map file "walktut_world" on vfs" and " could not open map file 'cally.cal3d' on vfs", I search some of the topics like my problem, and try to solve the problem. But it still can not run. I don't know why!
  Please help me,thank you !

I think i should change the vfs.cfg, but i don't know how to change it !