//#// first change to the framework directory and get the framework PEAR packages installed
cd /var/www/html/horde/framework/
php install-packages.php
//#// then finish
//#// needed for Horde base
pear install Log
pear install Mail_Mime
pear upgrade DB
pear install Date
pear install Auth_SASL
pear install File
//#// needed for IMP
pear install HTTP_Request
//#// needed for Wicked
pear install Text_Wiki
//#// needed for Ingo
pear install Net_Sieve
pear install Net_Socket
//#// needed for weather portal block in Horde
pear install cache
pear install net_dime
pear install Net_URL
pear install soap
pear install xml_util
pear install xml_parser
pear install serializer
pear install xml_serializer
pear install services_weather
//#// and lastly...
pear upgrade-all
If for some reason PEAR breaks...
then I just
cd /usr/share
mv pear pear.bak
rpm -e php-mysql php-imap php-ldap
//#// for RHEL 3 only
up2date php-mysql php-imap php-ldap php
//#// for RHEL clones
yum install php-mysql php-imap php-ldap php
and then back to the top and reinstall starting with
cd /var/www/html/horde/framework
php install-packages.php