There is an error message with the nxplayer for MAC OSX Lion 10.7 when connecting to AWS which you don't see in the other versions of MACOS/NXPlayer or MacOS/NXClient.
"the connection with the server was lost error is 22: invalid argument"
This error message can be debugged using the logs: nx/nx,messages=1,cookie=d53ef317b6b659fc37597ecb3e9907f6,shmem=1,shpix=1,font=1,samba=445,cups=631,media=6000,session=session,slave=1,id=ip-10-28-195-85-2000-5A6F2592D889884FD30861C8199C2DF1:2000
The port mappings for nxplayer changed. Add ports 631, 445, 6000, 2000 to your security group.
Also, do not reuse the old connection. This does not seem to work. Create a new connection a new instance instead of reusing the old configs stored in config files.