If you are using P3D V4, that's a known bug that doesn't have anything to do with GSX (that's why it cannot be solved by reinstalling, since it's not a GSX problem), and it affects every addon that use Simobjects, and it's related to the number of addons installed.
There's nothing we or you can do to fix it, because it's a known P3D bug (happens only with 4.1, not with 4.0), other than waiting for a fix from LM, which is aware of the issue.
