My Brother printer's error state only occurs when printing specific types of documents (e.g., PDFs with complex graphics). What could be the cause?

This suggests a compatibility issue. The printer might be struggling to process complex data or specific file formats. Try converting the document to a simpler format (e.g., plain text or a different PDF setting) or printing a test page to see if the error persists. Also, check if the printer supports the specific features used in the document.