Having trouble making reservations to use Rail Europe pass.

On line where? Italy or Rail Europe? For Italy, no need for advance reservations, Wait till you get there. Are you aware of the extra fees for making reservations? Generally a rail pass is not economical in Italy.

You can make them at www.italiarail.com. It is $12 for high speed trains with a 2nd class pass. You'll see a small box lower right with the words "I have a Eurail/Interrail:" followed by a choice box. You will then have to read the statement and "Accept". Then put in the cities and dates you want and the results will show all the available trains to choose from.
I don't know if there are any additional fees with this.

I think you have made a huge financial mistake in buying a railpass for Italy. Please read this article from the very highly regarded Man in Seat 61 about railpasses in Italy. Return the pass.

http://www.seat61.com/Italy-trains.htm#Railpasses_for_Italy

I would agree with the others: return the pass if at all possible as it's not a good deal for train travel in Italy.

Not knowing Susie's exact train plans, and having seen that she received the advice several weeks ago about trains, I wouldn't want to jump straight on to the mistake bandwagon.

Unlikely as it is, there may very well be special circumstances in her purchase of the rail pass for only Italy that make it either a bargain for her - perhaps many very long distance trains during the life of the pass, or perhaps she is unable to deal with the pressure of planning trains. Or perhaps the cost doesn't enter into it.

We don't know her circumstances so we shouldn't judge.

Great reply, Nigel!

You are right, Nigel. As it's usually so unlikely that passes in Italy can be a benefit that it's easy to just assume that'll be the case here. It may not be.