No worries at all! It seems like it might be a permission issue and I understand how frustrating this can be. The steps provided here should help, but if not, could you please share the following details:
Version of Illustrator and operating system.
A screenshot of the error.
Where the file is saved (system HDD, shared location, network drive, or external HDD).
With this information, I can better assist you. We’re here to help!