Install Auth on a debian

Hi First, excuse my english 2nd, I have a probleme with the Auth module of pear I want to try a product wihch need Auth package. (www.dolibarr.com) I have a debian distrib (3.0 RC2) with the php4-pear package (4.1.2-6) In the final product documentation, it is specify to install the Auth package. (Without, here is the message : Fatal error: Failed opening required 'Auth/Auth.php' (include_path='.:/usr/share/pear') in ;;;;) I download the last stabel package on http://pear.php.net/package/Auth and when I want to install it, here is the command line message : #pear install Auth-1\[1\].2.3.tgz <br /> <b>Warning</b>: unserialize() failed at offset 0 of 254 bytes in <b>/usr/share/ pear/PEAR/Config.php</b> on line <b>85</b><br /> PEAR_Config::readConfigFile: bad data<br /> <b>Warning</b>: Use of undefined constant checksum - assumed 'checksum' in <b>/ usr/share/pear/Archive/Tar.php</b> on line <b>698</b><br /> <br /> <b>Warning</b>: Use of undefined constant checksum - assumed 'checksum' in <b>/ usr/share/pear/Archive/Tar.php</b> on line <b>698</b><br /> <br /> <b>Warning</b>: Use of undefined constant checksum - assumed 'checksum' in <b>/ usr/share/pear/Archive/Tar.php</b> on line <b>699</b><br /> <br /> <b>Warning</b>: Use of undefined constant filename - assumed 'filename' in <b>/ usr/share/pear/Archive/Tar.php</b> on line <b>711</b><br /> <br /> <b>Warning</b>: Use of undefined constant filename - assumed 'filename' in <b>/ usr/share/pear/Archive/Tar.php</b> on line <b>711</b><br /> <br /> <b>Warning</b>: Use of undefined constant mode - assumed 'mode' in <b>/usr/shar e/pear/Archive/Tar.php</b> on line <b>712</b><br /> <br /> <b>Warning</b>: Use of undefined constant mode - assumed 'mode' in <b>/usr/sh If someone have an idee ?? Thanks, OZIT