"Position lights" are what Volvo calls all of the exterior bulbs that are On in the center position of the headlight switch. We used to call these "parking lights" in the USA.

In the center switch position, these lights remain on even when the ignition is turned off. If you have the warning message all of the time, try the following:
In the dark, turn them on and carefully compare the lights on the left side to the right. Pay partucular attention to the the two tail light bulbs, mounted one directly above the other. If any bulb appears dimmer than its counterpart on the opposite side, it is suspect and should be changed.

If the message comes and goes (intermittent), there could be a loose bulb in a socket. The only solution is to change them one at a time. All are standard sizes available at auto stores (like Pep Boys or Autozone) and discount stores (like WalMart), usuakky for less than $1.50 each. Any garage can change them for you in 30-60 seconds. If you want to try it yourself, instructions (somewhat cryptic) are in your Owner's Manual.

This will solve the problem most of the time. A bad current sensor (rare) can also generate a false message. In that case, I'm araid the 65 mile trip is warranted.