I ran into the same issue with SVREG and the USC Lobes Atlas. It turned out that the paths in the manifest file were off. I double-checked and realized the files weren’t in the folder SVREG was looking in. Make sure the file paths in your manifest are correct and that the files are named exactly as SVREG expects. I also re-downloaded the atlas just to be sure. If you’re still stuck, it might help to go over the setup instructions again or reach out to the support community for more specific advice.