Originally Posted by Tokyoite

It has been reported numerous times. Depends on the airlines/route you are trying to book (phantom award space), credit card you are trying to use (some cards are blocked by CC vendors from use in Colombia, where Lifemiles is based) or a simple Lifemiles error.

Did you get a screen with a PNR (booking code) before this screen?
If you did, I hope you noted the PNR down. Call in to complete the booking.
If you didnt, try the booking again.
If it persists, check on other award programs (united/aeroplan/ana) if the award space is really there, one flight at a time.
If the award space is there and the issue persisits, try another easier to get route and see if it errors. Use the wrong CC number just so that you wont get charged for the booking, and see if an error comes up. (E.g. NRT-ICN or FRA-MUC or EWR-ORD).
If it still persists, , wait a day to try again.
If you are still stuck, give up?