[horde] Strange variable

[johan]

Hi,

I work under debian woody, apache 1.3.26, php 4.2.3, mysql, horde2.1,
imp 3.1 Since upgrade to php 4.2.3 
horde2 cannot be loaded anymore due to not recognising of variable
server_key. Errors I receive : 

Warning: Invalid argument supplied for foreach() in
/usr/share/horde2/imp/login.php on line 114 
Notice: Undefined variable: server_key in
/usr/share/horde2/imp/login.php on line 126 
Notice: Undefined variable: server_key in
/usr/share/horde2/imp/login.php on line 127 
Notice: Undefined variable: server_key in
/usr/share/horde2/imp/login.php on line 128 
Notice: Undefined variable: server_key in
/usr/share/horde2/imp/login.php on line 129 
Notice: Undefined variable: server_key in
/usr/share/horde2/imp/login.php on line 130 
Notice: Undefined variable: server_key in
/usr/share/horde2/imp/login.php on line 131 
Notice: Undefined variable: server_key in
/usr/share/horde2/imp/login.php on line 132 

When I do the imp-test on http://spiderke.mine.nu/horde2/test.php
everything is fine, excepted PEAR Unknown error: Constant pear_os
already defined 
the imp test works fine , i.e. sending and receiving mail with the imap
server. 

Anybody has an idea ?

Greetz and thanks,
Johan