Just do what Cusco says, it worked in mine,
go to Start
If your using Vista in 'Start Search' or execute just type 'Regedit' + Enter
There will be window popped on screen, at right frame search in this sequence
HKEY_LOCAL_MACHINE -> Software -> Microsoft -> Office -> 11.0 -> Delivery
You should have this key 90000409-6000-11D3-8CFE-0150048383C9
click on it and
then go to the right screen or frame, right click on CDCache key.
and type 0 as new value
You don't have to reboot, it will perfectly work on that
Cusco....Did I thank u? Again thank u...