Hello,
I have an identical error.
avec autologin_for_xoops2.0.14JP and XOOPS 2.0.14-rc1

Fatal error: Call to undefined function: getinstance() in /mnt/117/free.fr/0/d/echecsdammartin/include/common.php on line 39

Yours sincerely

Here the file errorhandler.php

defined( 'XOOPS_ROOT_PATH' ) or die();

require_once XOOPS_ROOT_PATH . '/class/logger.php';

/**
* Backward compatibility code, do not use this class directly
*/
class XoopsErrorHandler extends XoopsLogger {
/**
* Activate the error handler
*/
function activate( $showErrors = false ) {
$this->activated = $showErrors;
}

/**
* Render the list of errors
*/
function renderErrors() {
return $this->dump( 'errors' );
}
}

?>