Error when installing

Error log

Code:

An exception occurred: Please enter an ID using only a-z, A-Z, 0-9, and _ characters. in /home/xxxx/public_html/library/XenForo/DataWriter.php on line 1345

    XenForo_DataWriter->_haveErrorsPreventSave() in XenForo/DataWriter.php at line 1387
    XenForo_DataWriter->save() in Brivium/AdminStyleSystem/Model/AdminTemplateModification.php at line 63
    Brivium_AdminStyleSystem_Model_AdminTemplateModification->importBriviumAdminTemplateModefication() in Brivium/AdminStyleSystem/Deferred/RebuildAllAdminTemplate.php at line 30
    Brivium_AdminStyleSystem_Deferred_RebuildAllAdminTemplate->execute() in XenForo/Deferred/Atomic.php at line 66
    XenForo_Deferred_Atomic->execute() in XenForo/Model/Deferred.php at line 294
    XenForo_Model_Deferred->runDeferred() in XenForo/Model/Deferred.php at line 428
    XenForo_Model_Deferred->_runInternal() in XenForo/Model/Deferred.php at line 373
    XenForo_Model_Deferred->run() in XenForo/ViewRenderer/Abstract.php at line 352
    XenForo_ViewRenderer_Abstract::hasManualDeferredToRun() in XenForo/ViewRenderer/HtmlAdmin.php at line 130
    XenForo_ViewRenderer_HtmlAdmin->renderContainer() in XenForo/FrontController.php at line 618
    XenForo_FrontController->renderView() in XenForo/FrontController.php at line 158
    XenForo_FrontController->run() in /home/xxx/public_html/admin.php at line 13