I believe you may have out-leveled him. It happens. What level are you now?
If you are level 8 or higher, the only way to continue the game is to find another contact. On your Contacts window, there should be a button labeled "Find Contact." If it shows you a new contact ("You do not know this contact"), you'll be give the option to Teleport straight to them.
If that doesn't work, head to Kings Row. Find your Dectective (either Freitag or Becktrees) and run their police radio missions. You get a nice temp power at the end if you can prevent Atlas Park Bank from being robbed.
If you've out-leveled Aaron's missions (or anyone's), you'll have to wait till you're level 15, then ask in broadcast for someone to open an "O-Portal" for you. This will let you access Ouroboros, a time-traveling zone whos main feature is to let you play out-leveled and removed content. First, head to the top of the floating structure to get the exploration badge. This will net you "Entrusted with the secret" and let you have your own O-Portal.
Then, head inside the structure, and click one of the little crystals. They'll pop up with a list of all the story arcs that you may have missed (any you've finished will be gold and labled with a star). Find Thiery's arc (his picture will be next to it, and it should be in the 1-10 range), then click the giant crystal to teleport to him, and you'll be all set!
-STEELE =)
Allied to all sides so that no matter what, I'll come out on top!
Oh, and Crimson demands you play this arc-> Twisted Knives (MA Arc #397769)
Cool, thanks a lot!
I went to Aaron Thiery for the next mission, but when I started talking to him, one of the those robot bad guys started attacking me. So I left the conversation and defeated the robot. I went back to talk to Aaron, but all he said was basically that we couldn't work together anymore. How do I fix it so I can continue the game?