With a mission that seems hopelessly bugged, I had to log out for an extended period of time in order to clear it up. But then again, I also filed a ticket on it, so maybe a GM snuck in there and reset that part of the mission for me.
In essence, file a ticket. I remember that mission and there wasn't anything special I recall doing to finish it.
I had the same thing on a klingon mission. An NPC let 2 super gorn out of their forcefields and attacked me. The game then crashed and when I got back in the gorn had reset but I was unable to even target them never mind attack them. Anyway I tried leaving the system, then quit for the night and tried again the following day but no luck.
I contacted a GM about it using the stuck option and was replied too a few hours later. They said I had to restart the mission which was annoying as it was a two parter. I restarted the mission and it happened again (the game was crashing because due to the ATI card issue). Third time I was lucky and it didnt crash so I completed the mission.
Long story short you will probably have to abandon the mission and start again.