Have you updated all of your 162 software? I had to do that before I could download selected Fishing Hotspots maps.
Are you sure that when you downloaded unlock codes that the serial number of your unit matched the unit you are trying to download to? Unlock codes are specific to one unit and cannot be used to unlock a different unit.
This prevents an unlock, which amounts to an exclusive license, being used on more than one unit.
Hope that helps.
Red sky at night. . .
JB