You posted your panic log, which is not detailed enough to understand the situation, and you haven't said which airplane you used, if it's supported by GSX and/or if you made or changed its configuration, all information which would have been present in the Couatl.LOG that is created when Logging is enabled in the Troubleshooting section of the GSX Settings.
From the error, it seems there's a problem with the airplane profile so, either try to be more precise about the airplane used and its configuration, or enable Logging in the Troubleshooting section of the GSX Settings and post a Couatl.LOG file instead of the short panic log.
Also, if you are using a custom airplane profile, post that one as well.