[horde] Problem with new installation horde 2.2.1 imp 3.2

[Steve]

We were running the old horde 2.0.2 with imp, and have just upgraded all
modules and reinstalled.. 
We're getting this error though :

Fatal error: Cannot redeclare class auth in /var/www/horde/lib/Auth.php
on line 21

Can someone shed any light on this ???

We've done a fresh install.. The test.php results for horde are  :

Horde Versions
Horde: 2.2.1 
IMP: 3.2 (run IMP tests) 
PHP Version
View phpinfo() screen 
PHP Version: 4.3.1 
PHP Major Version: 4.3 
PHP Minor Version: 1 
PHP Version Classification: release 
You are running a supported version of PHP.
PHP Module Capabilities
DOM XML Support: No 
Gettext Support: Yes 
IMAP Support: Yes 
LDAP Support: No 
MCAL Support: No 
Mcrypt Support: Yes 
MySQL Support: Yes 
PostgreSQL Support: No 
XML Support: Yes 
Miscellaneous PHP Settings
magic_quotes_runtime disabled: Yes 
file_uploads enabled: Yes 
safe_mode disabled: Yes 
trans_sid disabled: Yes 
PHP Sessions
Session counter: 8 
To unregister the session: click here 
PEAR
PEAR - Yes 
Recent PEAR - Yes 
Mail - Yes 
Mail_Mime - Yes 
Log - Yes 
DB - Yes 
Net_Socket - Yes 
Date - Yes 
HTML_Common/HTML_Select - No 
Horde requires the HTML_Common and HTML_Select classes only for
Kronolith 1.0 to display forms correctly.