Note to others that don't answer these questions correctly: Giving a false statement sends other readers in the wrong direction. You're not only giving false or misleading information to the person asking the question, you're giving this information to the general public that searches and finds this question in the future. Please answer responsibly.
Answer: "Unable to determine registration fees due. Current application in process." This means that either there was a lien sale on the vehicle, most likely from a tow yard, and the DMV needs the lien sale packet to transfer title free and clear. This doesn't mean that there had to be a "lien" on the vehicle.
A lien sale is a way to transfer ownership through establishing a burden to the landholder from having to store a vehicle LEGALLY on their property. Or, someone sold this vehicle and went to the DMV to start the transfer (more likely the case in most situations). If the latter is the case, the new owner will have to bring all of their paperwork to the DMV with chain of title to prove that it was purchased legally down the line from the registered owner.
If the chain of title is broken, and the new owner cannot get in touch with the previous owner that broke the chain of title, the new owner MAY IN CERTAIN CIRCUMSTANCES be able to still register the vehicle with a Statement of Facts. However, this will create a cloud on title for up to 3 years, in which time the previous owner in which you're missing the paperwork from may seek ownership interest for the vehicle through court action.
Always get all the signatures and sign off a vehicle properly. Otherwise, you may be losing money if a cloud causes a previous owner to regain interest and ownership in a vehicle, leaving you without any recourse and no asset to show for it.