You could also try resetting Dashboard without restarting. After looking into it, I figured out that Dashboard is actually an extension of the Dock application, so you weren't far off when you said your dock was stuck.
Open Terminal (Applications > Utilities > Terminal.app) and type this in:
Remember, it's case sensitive. Now hit return, and try the Dashboard again; the dock will automatically restart.
If it's still not working, there may be a problem with one of your widgets, that's somehow preventing the rest of the widgets from starting up. Try removing all your widgets from the 'active' screen and put them back on from the Widget bar. See if one of them is causing the problems.
Check and see if that widget has an update.