Could dried ink be the cause of error code 5100, and if so, how do I address it?

Yes, dried ink can sometimes contribute to error 5100, as it can cause the print head to stick. Try cleaning the print head using the printer's built-in cleaning utility (usually found in the printer's maintenance settings or via the printer driver on your computer). You might need to run multiple cleaning cycles. Also, consider performing a deep cleaning (if available) as described in your printer's manual if normal cleaning is insufficient.