dreamweaver trial


I just downloaded the Dreamweaver Trial, and I am having trouble selecting the 800X600 pixel size.  When I click on the current size, it gives me a list of different size options, however, they are all greyed-out and will not let me select a different size.  Does anyone know what the problem could be?   Since it is a trial, do I not have the option to change the size? If so, does this mean that using the trial is not an option since our webpage has to be 800 X 600 pixels?