# first change to the framework directory and get the framework PEAR packages installed
cd /var/www/html/horde/framework/
php install-packages.php
# You will need to download these two packages to complete the pear installation
wget http://dag.wieers.com/packages/php-sqlite/php-sqlite-1.0.2-1.rhel3.dag.i386.rpm
wget http://dag.wieers.com/packages/sqlite/sqlite-2.8.16-1.1.el3.rf.i386.rpm
# needed for Horde base
pear install Log
pear install Mail_Mime
pear upgrade DB
pear install Date
pear install Auth_SASL
pear install File
pear install Net_URL
# 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 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