Late Sunday afternoon. The AppleCare Senior Tech Advisor called and said that after remote analyis of my system, they noticed a lot of timeouts reguarding my desktop wallpaper pictures that were set up to rotate.
Previously, I copied a number of my phots into a folder where the Stock Apple desktop backgrounds are located. I then selected my photos and set them to to rotate in the normal manner. This worked fine under OS Lion but may have caused a conflict under OS Mountain Lion.
The Tech Advisor had me change the desktop background to a standard Apple background and reboot the system. After testing for about three or four hours, It looks like this was the fix for me. Wakeup from sleep, no problem, I now have full functionality of the dock again.
Previously, I tried to delete the file "com.apple.dock.plist" from the library/Preferences folder and reboot. This did not help me but you may give it a try. No harm done if it dosn't work. The operating system will rewrite the file during a reboot. If the file was corrupted, this may help.
Some further information: My system is a Mid 2011 Imac 27" and I am running dual monitors. This was a strange bug systems bug so I suspect it may be any number of things causing the problem.
Good luck. I hope uou fix yhe bug.