When I load another level in a level,it says "can't save and load in the same frame".
What is it?

did you save the old level and try to load another level in that frame? you need to put a "wait(1);" in there so they won't try to happen in the same frame.

the "wait(1);" is your friend, but know when to use him and when not to.

I think you have to write wait(2) in your script. I've copied that text (because I 'm not able to write in this language):
The current level will terminated.
One frame cycle after this instruction the level is loaded, two frame cycles after the instruction the local entities in the new map are created and their actions are started.