Simple RAW Thread for 3.5 #32: More Seasons than the Simpsons

[kkplx]

Q152

Could I ready an action to cast Dispelling Screen to:

a) Place the wall in the way of one side of a wall of fire or similar to stop it from expanding that way?
b) Place the sphere or hemisphere, or a shaped wall around the origin of a wall of fire or similar to entirely contain it within its originating intersection?

This assumes I know the spell is being cast, which triggers the readied action.

Since the spell says "Spell effects not operating on objects or creatures cannot pass through the screen.", I assume that the above uses should be possible.

Q153

Could I place a dispelling screen on the origin of a wall spell after it has been cast to completely confine it to inside the dispelling screen's sphere, since i'd cut off the origin of the effect?