That would be a bios lock. You need to contact dell to remove it which they will be happy to do so long as you can verify you are the owner of the machine.
Where are you getting this prompt? Sadly that error code doesn't mean anything to us (it isn't universal) so we need more information.
That is the message you get when you attempt to enter an admin locked bios or a hard drive locked dell system. The first set of digits is the service tag and the second part is part of the system identifier they can use to generate an unlock code.
Dell will unlock it for free so long as he can verify himself as the owner. Otherwise there are several services that will attempt to unlock it and they run about 40-100$.
Also if you lucked out and it is just a hard drive password you can just trash the drive and put in a new one. But typically machines with the drive password also have an admin one. You can test this by removing the drive and pressing f2 on boot and seeing if it will go into the bios. If it doesn't then its locked at the bios, if it does then its locked at the drive and you can just replace the drive.