must agree with Addicted then, sounds like its software related, either contact them and see if there's an update or issue with your o/s etc
after a google search it seems that its not fully 64 bit compatable either,
If for whatever reason you cannot access RocketDock's Settings and need to completely reset RocketDock to "factory default" settings/icons, follow these steps:
Press Control+Alt+Delete and use the Task Manager to force-quit RocketDock
If you are NOT using "Portable INI Settings" (recommended), follow these steps
Go to the Start Menu, choose "Run" and type "regedit"
Browse to HKEY_CURRENT_USER\Software\
Delete the "RocketDock" folder
If you ARE using "Portable INI Settings", delete the file "Settings.ini" located in your RocketDock install directory (C:\Program Files\RocketDock\Settings.ini).
Run RocketDock, and enjoy!
type shell:startup into Start/search and hit Enter) and drag a shortcut of the RocketDock.exe (from Program Files x86) from the desktop into that folder.
some more info to try as well just found,
it tends to hang on start up if there is no log in password. So if you don't use a password at log in, try creating one and see if it helps (for 64bit only)