We are sorry for the trouble. I would request you to share a few details like:
The exact version of OS and its built number
The exact version of Illustrator
When did this start happening? Are there any recent changes made to your system? For example, any antivirus, system updates, plugins, or web extensions installed recently.
Would it be possible for you to compress the Startup Script folder in theZip filefrom the location mentioned in error and upload it to Creative Cloud/ Dropbox or any other similar service and share the download link here with us?
Also, when does this error pop up while launching the app or while using the app? Does the app close/ crash or start not responding after clicking on the "Ok" button?
We are here to help. We just need more information.