QuickForm php warning using DB_DataObject_FormBuilder

Hi All, I'm getting this error when using the $form->toHtml method of quickForm: Warning: htmlspecialchars() expects parameter 1 to be string, array given in /usr/local/lib/php/HTML/Common.php on line 140 The form was created using DB_DataObject_Formbuilder, and this is only happening in one specific instance, otherwise FormBuilder works great. Now... I'm not sure how to backstep and find out exactly which method is calling that. Line 140 is inside the _getAttrString() method, which seems to only be called by the getAttributes() method in Common.php. Running: /usr/local/lib/php/HTML/QuickForm$ grep getAttr * I get 34 results in different files... can anyone recommend a better way to debug this so I can find out what's causing this error? Thanks, Dan