My bet is that it is installed, but you need to find a way to see it.
The only evidence on my XP pro SP2 to see the Hotfixes is in the
Add/Remove programs with the "check box" enabled. See below.

Be that as it may, If you really believe it is not installed, after you
install the OLCONN2.exe file how are you setting up the server?
There is an installation instruction that is in the exe file that
installs in the Outlook Connector directory (should install in
C:\Program Files\ Outlook Connector\InstallationGuide.htm that has the
instructions for setting up the connector before you run Outlook. Its
important that you follow those instructions. using the MAIL icon in
the Control Panel

I would still pursue the Hotfix as a potential. The Show Updates
checkbox is a Win XP SP2 feature. The fact that you don't see the
"show updates" checkbox in the Add Remove programs may mean that your
Corporate IT disabled it by group policy. You can turn it back on if
your willing to edit the registry. There are instructions for diabling
the checkbox under support.microsoft.com article 884786 titled "How to
manage the Currently installed programs list in Windows XP Service Pack
2 and in Windows XP Tablet PC Edition 2005". You would use a 0 for
DontGroupPatches to re-enable it.

Hope this helps.

Paul