For some reason, when I removed and replaced toolbars in an .mxd document the Layout toolbar is greyed out. I've tried opening/closing the document and ArcMap, in addition to readding the toolbar several times, and also tried going into Data Frame Properties and ensured that automatic radio button was checked. Any suggestions for what I'm sure is a simple, yet annoying, problem would be much appreciated!
Make sure you're using the layout view. One of the 3 little buttons under the map data window, the left is data (map) view, the middle is layout view--this is when the layout toolbar is active, the right is refresh.