Create a second 'related user' field in a module

[Guido1982]

I tried the following code to add a "101" field to SalesOrder:

PHP Code:

include_once('vtlib/Vtiger/Module.php');

$module = Vtiger_Module::getInstance('SalesOrder');
$blockInstance = Vtiger_Block::getInstance('LBL_SO_INFORMATION', $module);

$fieldInstance = new Vtiger_Field();
$fieldInstance->name = 'reports_to_id';
$fieldInstance->table = 'vtiger_salesorder';
$fieldInstance->column = 'executing_user_id';
$fieldInstance->columntype = 'INT(11)';
$fieldInstance->uitype = 101;
$fieldInstance->typeofdata = 'V~O';
$blockInstance->addField($fieldInstance); 


This worked, but gave me the following error:

PHP Code:

Catchable fatal error: Object of class Vtiger_Module could not be converted to string in index.php on line 687 


Does anyone know what went wrong? As said, the field was created.