imp is broken now that I upgraded from php3 to php4

[Chris Blackstone]

I'm beginning the process to upgrade imp 2 to 2.2, and started by
upgrading the php (3 to 4) and apache (1.3.4 to 1.3.14) installs on the server.
I installed everything okay, but now when I login to imp I get messages like

"Warning: Can't connect to local MySQL server through socket
'/tmp/mysql.sock' (2) in /usr/local/www/apps/horde/imp/lib/db.lib on
line 253
"
and

"Warning: Undefined property: parts in
/usr/local/www/apps/horde/imp/mailbox.php3 on line 452"

I think it's a problem with my php install because when I tried to run
the test program ya'll have on the horde faq page it returned this error

"Warning: Failed opening '/usr/local/www/htdocs/test.php3' for inclusion
(include_path='') in Unknown on line 0"

Can anyone give me help with this? I apologize in advance if this isnt'
the right forum for this question

thanks
chris