All regions that will have fades must be"fully"selected. If there are regions at the beginning or the end that are partially selected, the program will not create the chosen fade between the partially selected region(s) and the region(s) it is connected to. Select all regions that are to have fades by using the "grabber"tool. Hold down the Shift key and click on all the regions to fully select them, then select "Fades" from the Edit menu.