Greeting,
Sorry to hear about the trouble. As per the screenshot, I found a similar discussion which you can refer here: https://community.adobe.com/t5/adobe-xd/extensibility-error-installing-plugin-in-xd/m-p/10848199?pag...
If above solution doesnot help, Please can you let me know few information, it will help me in debugging the issue :-
1. Which plugin you are trying to install.
2. Which version of OS you are working.
3. XD version
4. Creative cloud version.
5. It will be great if you send me the log of your machine using log collector: https://helpx.adobe.com/in/creative-cloud/kb/cc-log-collector.html
you can DM be log by clicking on my name, you will get my ID or attach here.
Thanks,
Vertika Gupta
Adobe XD