As I see there is missing PEAR class in the /tmp/roundcubemail-1.2.3/program/lib/Roundcube/bootstrap.php which has nothing to do with CWP as far as I know.
P.S.
With RoundCube personally I`m using also AfterLogic and RainLoop web mails. RoundCube and AfterLogic for users and RainLoop for me(because I like it more the way it looks). Go on their pages and you will find very useful and easy install instructions and scripts. Best wishes.