Hi @garcianava, 

Thank you for reaching out to our community.

It seems you might need some additional permissions to create Python notebooks. The message indicates you'll need the "dataform.repositories.create" and "aiplatform.notebookRuntimes.assign" roles.

@MaxImbrox shared a helpful document that details the required roles for the Python Notebook button.

For further reference, here are some resources:

• IAM: BigQuery Studio User 
• Python Client for AI Platform Notebooks