[pkg-horde] Problem with main panel following login

[Anthony Brock]

I recently replaced my web server with a Debian Etch installation. I  
then installed horde3, imp4 and kronolith2 to replace my older  
versions (all using the same database and my older versions). The  
documentation on www.horde.org indicates that the upgrade to your  
versions didn't require any database changes.

However, I'm now encountering the following error in the main panel  
after I login:

Fatal error: Cannot use object of type Cache_Error as array in  
/usr/share/php/Cache/Container.php on line 345

Fortunately, the side-panel is properly rendered. I am then able to  
click the "Mail" link and read/respond to email normally. However, the  
error reappears when I click the "Horde" link in the side-panel.

How to do I gather enough information to properly diagnose this issue?  
Nothing is appearing in the /var/log/horde/horde.log file other than  
login and logout notices. Is this a known issue?

Thanks!

Tony