Upgrade extension from 8.4 to 9.1

Hi,

sorry for posting this again, but my earlier questions did not appear in
the news server just on the webpage.

I am migrating databases from 8.4 to 9.1 using traditional backup and
restore. After restore to a clean database everything seems to be ok.
The only thing is that there are no extensions for my prior installed
modules. Do I really have to install extensions with "create extension
XXXXX from unpackaged"?
When I try to create the extension for "dblink" I get the following error:

ERROR: function dblink_get_notify() does not exist SQL Status:42883

In 8.4 I installed the module with the appropriate sql script in
share/contrib.
Now I ended up with uninstalling the module with the uninstall-script in
share/contrib and then creating the extension without "unpackaged". But
as we use PG in a product with a NSIS installer this makes the world
unnecessary complicated.

Thanks for your help in advance
Alex