Fehler beim Installieren

[TheXxX]

Hallo Leute,

ich habe mir vor einigen Wochen die Forensoftware XenForo gekauft, heute versuchte Ich sie zu installieren.

PHP & MYSQL ist auf dem neusten Stand.
WebServer: Apache2
OS: Debian 5 ( Linux )
XenForo-Requirements-Test = Alles Okay.
openbase = none
savemod = off

Fehler:

    Zend_Validate::is() in /var/www/web3/html/library/XenForo/DataWriter/User.php at line 507
    XenForo_DataWriter_User->_verifyUsername()
    call_user_func_array() in /var/www/web3/html/library/XenForo/DataWriter.php at line 899
    XenForo_DataWriter->_runVerificationCallback() in /var/www/web3/html/library/XenForo/DataWriter.php at line 667
    XenForo_DataWriter->_isFieldValueValid() in /var/www/web3/html/library/XenForo/DataWriter.php at line 585
    XenForo_DataWriter->set() in /var/www/web3/html/library/XenForo/DataWriter.php at line 912
    XenForo_DataWriter->bulkSet() in /var/www/web3/html/library/XenForo/Install/Model/Install.php at line 216
    XenForo_Install_Model_Install->insertAdministrator() in /var/www/web3/html/library/XenForo/Install/Controller/Install.php at line 273
    XenForo_Install_Controller_Install->actionStep3b() in /var/www/web3/html/library/XenForo/FrontController.php at line 310
    XenForo_FrontController->dispatch() in /var/www/web3/html/library/XenForo/FrontController.php at line 132
    XenForo_FrontController->run() in /var/www/web3/html/install/index.php at line 17