This error occurs when either input or output audio bundles have been duplicated. To prevent this error, go into the Studio Menu and open the Audio Bundles window(Shift-U is the key command). Click on the Input tab, select all of the bundles and delete them. Then click on the Output tab, select all of the bundles and delete them. Once you have done this, you can recreate all of the necessary bundles in the Audio Bundles window, or create them as they are needed by selecting New Mono/Stereo Bundle from the track input/output section. When doing this, make sure not to create any duplicate bundles. Once you have created all of the necessary bundles, save the project.