[RCU] Undefined methods Mail_mime::getTXTBody() and Mail_mime::setParam()

Hello list:

After upgrading to 0.7.2, I just saw that I receive the following error messages upon trying to send a message:

PHP Fatal error: Call to undefined method Mail_mime::getTXTBody() in roundcubemail-0.7.2/program/steps/mail/sendmail.inc on line 572

PHP Fatal error: Call to undefined method Mail_mime::setParam() in roundcubemail-0.7.2/program/steps/mail/func.inc on line 1462

OS is Ubuntu Lucid 10.04, and I have the following packages already installed and also tried reinstalling them:

dpkg -l |grep php |grep mail ii php-mail 1.1.14-2
PHP PEAR module for sending email ii php-mail-mime 1.5.3-0.1
PHP PEAR module for creating MIME messages ii php-mail-mimedecode 1.5.0-3
PHP PEAR module to decode MIME messages

Any idea what I could be missing? The exact same server was running 0.3.1 just fine, and also the 0.7.2 installer lists all requirements as present (in green).

Thanks in advance, Achim