phpunit error in ubuntu 11.04

Got below warning when run phpunit in ubuntu 11.04:

PHP Warning: require_once(PHP/CodeCoverage/Filter.php): failed to open stream: No such file or directory in /usr/bin/phpunit on line 38
PHP Stack trace:
PHP 1. {main}() /usr/bin/phpunit:0
PHP Fatal error: require_once(): Failed opening required 'PHP/CodeCoverage/Filter.php' (include_path='.:/usr/share/php:/usr/share/pear') in /usr/bin/phpunit on line 38
PHP Stack trace:
PHP 1. {main}() /usr/bin/phpunit:0

repair commands:

sudo apt-get remove phpunit
sudo pear channel-discover pear.phpunit.de
sudo pear channel-discover pear.symfony-project.com
sudo pear channel-discover components.ez.no
sudo pear update-channels
sudo pear upgrade-all
sudo pear install --alldeps phpunit/PHPUnit
sudo apt-get install phpunit