I ran into this problem on Monday as well. I was changing an award and wanted some segments in LH F. After getting the whole booking organized the agent was unable to complete the process because of an unexpected 'error' message on his screen. After 20 more minutes on hold I was told AE was having problems (since Friday March 13) booking LH F & C awards and I would have to try again later.

I hung up and decided to follow the FT mantra of call again and see if you get a different result. 30 minutes later I had my revised award ticketed using LH and LX F.

I was led to believe this is an internal AE IT issue.