To link to a folder;
Right click the icon, in the 'Link' field type,'explorer.exe',
in the 'Arguments' field, type in the path to the folder you wish to link to.
(example; C:Program Files)
To link to the Startmenu:
Copy and paste the following in a text editor.
set wShell=wscript.createobject('wscript.shell')
wShell.sendkeys '^{ESC}'
Save with .vbs extension. Pay attention to where you save it. Now link to the file in the Dock Item Properties.