i edited the "example.irr" to change the texture paths as well as fixing the 0.4 attribute problem...
anyway, all things went smooth... compiled, and run.
and i saw things like this:

how to make the black area of the light to become transparent?
and i noticed that when i move nearer to the room, parts of the room gone.
(as shown in the picture: parts the floor gone)
i think that but my own mistakes.
can anyone teach me how to fix it? thanks
(and sorry for my broken english)