Is this within ColdFusion Report Builder?
I tried to move this post to the Reporting subgroup of ColdFusion, but apparently I'm not allowed. You might try moving it there yourself (if you can).
I don't see a way to move the message other than copy and paste in that area. Is there an action to move a message?
Since you are the original poster and owner of this thread, you can move it. Just scroll to the top of this thread, and look to the right-side of the first post for "ACTIONS". There is an option to edit, and an option to move it.
I occasionally experience this error when trying to add a sub-report to a report that I have been actively working on.
To work around the problem, I close the report builder completely. I then open the parent report and, without making any other changes to it, I add the sub-report and it succeeds.
Unfortunately this problem will never be resolved because the ColdFusion Report Builder is deprecated and is no longer supported.
I highly recommend you find another server-side reporting solution.