The Zoho Creator variable zoho.adminuserid is the email ID you'd used while signing up with Zoho. It is also called your Primary Email ID. 
To change your zoho.adminuserid/ Primary Email ID

• Visit https://accounts.zoho.com.
• Sign in using your Zoho credentials.
• From the left pane, click on "My Email IDs".
• Click on the "Add New" button.
• Enter the Email ID which you would like you use as the "Primary Email ID" and your current Zoho password.
• Click on "Add" to add the newly Entered ID.
• Click on the "Edit" link displayed next to the Email id and check the "Is Primary" checkbox and click Save.
• A star will be displayed next to the ID to indicate that the ID is the Primary Email ID of your account.
• A confirmation email will be sent from Zoho.
• Click on the link contained in the email to validate your email ID.