Chronoform Plugin CB Registration

Hello Together.
Frameworks: joomla1.5.14
CC 5.5

I whant to register a new user with chrono and inserting into CB.

It works fine overall this "bridges"😀
if I whant to register an existant user or e-mail , the plugin (cf_cb_registration.php)
returns only false;
Have somebody scripted in the past en "extension or workaround patch"?

Thanx for anwering

Solution found by my self😶
step 1::
cf_cb_registration.php line::258()
// If there was an error with registration, set the message and display form
if ( !$user->save() )
{
//JError::raiseWarning('', JText::_( $user->getError()));
return $MyPlugins->cf_cb_registration['errors'] = JText::_( $user->getError());


}
step2::

plugins.php line::122
if ($params->get('onsubmit') == $emailevent)
{

$MyForm->formerrors = ${$ava_plugin}->onsubmit('com_chronocontact', $params, $plugins[0]);
}

::finished then it will be function, but I Have not checked the code around for resulting errors of this changes