I want to create a new version of my OP but receive the Error message: "Error during commit: program version to create already exists".

You are probably trying to create a NEW PROGRAMME and not a NEW VERSION of the EXISTING PROGRAMME.

To create a new version of an existing OP:

• Go to the "Programming" > "Operational Programme" menu
• Click on the "CCI" of the latest version of the concerned OP (in your case "Version 2")
• The Operational Programme contents appear in the screen
• Click on the link "Create a New Version of the Operational Programme"
• Version 3 is created

The option "Create a New Operational Programme" (at the bottom of the general list of OPs) allows to create a fully new programme and not a new version of an existing programme.