After upgrading you probably restored a backup, this added all your old repositories back to the list. However those repositories are all set up for the 'bora' (OS2007) distribution. To install applications that were built for OS2008 you would have to change all the application catalogs in the application manager to the 'chinook' (OS2008) distribution.

btw. I noticed that when I leave the distribution field empty, the application manager seems to default to the correct distribution name. Not sure if this is new behaviour.