Hey, I need a very quick aswer!
I have make a box dropper and drop a box when the map starts. and when the cube be destoyed in the "portal cleaner" I want the box dropper respawn a new box.. Please tell me how to make this. please

Thanks!

You need to place an env_entity_maker (i think...) at the center of the cube. Then set template 1 to the name of the cube. Then, goto your cleanser and give it the output:
onboxdestroy
name of entity_maker
ForceSpawn
0.00
0

That should do it!

You'll need to name your prop_physics "box" for this to work. I know that's how it's done cause I read it here.

/end shameless_plug_for_tutorials

Bizob, be shameless. Those tutorials are there for a reason, and the answers to this question are (I believe) contained in the Wiki already.

Just waiting there for the taking.