Hi Dan,
I'm glad to hear that the iRODS integration is going well. With regard to the error you mentioned, that file is used to capture the results of automated bit integrity runs that are managed by DuraBoss. The reason that error are showing up in the logs is because every time you attempt to view a space via DurAdmin (the UI), it looks to see if there is a bit integrity result for that space that can be displayed. To do that, it tries to access the json file, which is not found, resulting in the error. So the error is not anything to worry about, it won't cause any issues. If you'd like to keep the errors from showing up in the logs, you can place the attached json file in a space named x-duracloud-admin.
You may also see errors in the logs indicating that the "logo" file cannot be found. These show up for a similar reason, DurAdmin is looking for that file to be able to display it. You can drop the attached logo file into x-duracloud-admin as well to prevent those errors from occurring. You can also use your own logo file, if you prefer, just make sure it is named "logo", with no extension. The logo image will be displayed in the upper right-hand corner of the UI.
Bill