I clear installed CMDCam mod and i don't know why but whae i try command like "/cam add 1" or "/cam set 1" i got: The given index '0' is too high/low!

Just use /cam add, if you add it will try to insert the point before the given index, which is impossible because your list is empty. Same goes for set , it will try to replace the first point, which does not exist.