I installed Tiger and never had this problem...As you said there might exist a program that is trying to update or just plain ring home but the fact that that the message "couldn't find server" is coming from internet connect makes this less probable IMHO.
For what its worth why don't you try installing a trial version of Little snitch
. It will give you the name of the application that is trying to access the internet and the option to either deny the application ( deny forever or until the application quits ) or allow the application (forever or until the application quits ).
About dash board, try disabling active screen corners and deleting the icon from the Dock. Then open up terminal and type "killall Dock". That way Dashboard will be unloaded from memory and will not be accidentally triggered.
Hope it helps.