[horde] domxml error

[Blackwire Server]

I have installed Horde 3.0.2 framework and it keeps barfing on me when
trying to finsh my setup.

---error snippet-------------------
A fatal error has occurred
You need the domxml PHP extension to use the configuration tool.
[line 25 of /var/www/html/mail/horde/admin/setup/config.php]
--end snippet-----------------------

running php 4.3.8 and apache 2.0.52

my phpinfo indicates that 
'--with-dom=shared,/usr' '--with-dom-xslt=/usr' '--with-dom-exslt=/usr'

so it looks like php was compiled with domxml, but I can't find the
freakin' file anywhere....

really, it is getting frustrating...I found a link to PECL but there
is no php-domxml pkg.

google spits out a bunch of rubbish when searching ...I found 30
phpinfo() sites, no info on this ...

TIA for help and suggestions