when the error message appears, please press CTRL+ALT+F4 and send us a clear and readable picture of the error message.
then press CTRL+ALT+F1 or CTRL+ALT+F5 to go back to the installer and shut it down properly.
We will be able to help you once you send us this screenshot.
Of course you have to make sure to download the latest version of Parrot. This means that you have to trash 4.1, 3.11 or any precedent version and make sure to have Parrot 4.2.1 or later.
then follow the guidelines described in the following links: