Hi, I had the same issue. The problem comes from the fact that CS5.5 has not been develop to works with Lion. Unfortunately the bug has not been fixed and I don’t know if it will. So you have 2 solutions :
-donwgrade your OS (go back to Leopard)
-upgrade your Adobe Premiere Version, CS5.5 to CS6
I choose the second solution, but obviously the first one is cheaper…