Hi Lou,
I would suggest an uninstall of FlyInside, and clear out all the files it creates, such as the Flyinside.cfg file. You should find info on how to do a complete uninstall on their website. Then make sure you have the latest version. I just discovered last night that I didn't have the latest version for P3DV3, and all the versions have received updates quite recently.
Also post on their forum if you are still having issues. Dan (the developer) and Tony are usually very helpful.
Cheers,