Under windows you have to launch blender with the Start > "run" command by typing "blender.exe" into it.
Under Unix (Mac/Linux) you have to open up a terminal and type "blender".
Open up the file causing the bug.
Repeat the steps causing the bug.
Look into the terminal/console and copy the error-message that might have showed up in it. It's best If you copy everything, so the developer gets as much information as possible.
Create a post at x-plane.org / Or open up an issue at Github containing the following information: Your Operating System, your XPlane2Blender version (e.g. 3.20r1), your Blender version together with the build-number (if using Blender 2.5x this is the number after the "r"), the exact steps for reproducing the error, the error message(s), if possible the file causing the error cleared of all non-relevant parts for the bug.
Wait and hope. We will look into it and fix it asap.
Please only send me private messages/email to send me the buggy files. Do not send me your bug report in a PM or email. Making the bugs/problems and their solutions public will help all other users of XPlane2Blender with the same problem.