Interesting. It's a low-level error, so if you turn down your error reporting is should at least allow the script to run. Try this in the meantime
I assume you're using a custom gridLabelField? Add ->XML_val to the return values of the obj() method.
506 public function FileLabel()
507 {
508 if($this->parent->gridLabelField)
509 $label = $this->obj($this->parent->gridLabelField)->XML_val;
510 else if($file = $this->obj($this->parent->fileFieldName))
511 $label = $file->Title->XML_val;
512 else
513 $label = "";
514 return strlen($label) > 30 ? substr($label, 0, 30)."..." : $label;
515 }
516
517 }
518
If that works, let me know, then undo all your changes to the class and I'll check in a new version. thanks.