Pear doesn’t let you install pear DB because it is an old version that comes with the Virtualmin install. I have gotten around this by forcing it to install and upgrade. Squirrelmail cant be used without it.
First install pear:
yum install pear
Then type these:
pear upgrade –force Console_Getopt
pear upgrade –force pear
Now pear is upgraded and you can now install pear DB.
pear install DB
There you have it. Now you can use Squirrelmail for your mail.