[rt-users] Can't locate object method "_Accessible"

[CLOSE Dave (DAE)]

My server is running Fedora 8 and was running RT 3.6.5 ok. Most files 
were located in /usr/share/rt3. I have just upgraded to RT 3.8.7 and 
changed the installation directory to /opt/rt3. All references in 
/etc/httpd/conf*/* have been changed to refer to /opt/rt3 but the 
/usr/share/rt3 directory is still present. RT is running on port 8080 to 
avoid conflict with another application.

After the upgrade, RT refuses to run. The log shows this message:

[Fri Apr 16 15:04:34 2010] [error] [client 172.16.100.228] Can't locate
object method "_Accessible" via package "SubscribeDashboard" (perhaps
you forgot to load "SubscribeDashboard"?) at
/usr/lib/perl5/vendor_perl/5.8.8/DBIx/SearchBuilder/Record.pm line
423.\nCompilation failed in require at /opt/rt3/bin/../lib/RT.pm line 443.\n

Looking around online, I don't find this specific message referenced 
anywhere. However, similar messages with other methods are quoted. The 
general idea seems to be that something isn't up-to-date as expected. So 
I've run "yum update" on the server and updated everything. I then used 
cpan to update File::Temp since the repositories don't seem to be 
current for that module. After restarting the web server (Apache 2), RT 
still fails in exactly the same way.

Obviously, I'm still missing something simple. Can anyone tell me what?
-- 
Dave Close