There is a known situation where jobs with 'Simple job costing' enabled and estimates that have a phase and/or category for some reason generate the error message on the cost batch listing report. This does not adversly affect posting, just the list report. It is currently in development's hands.

In my tests, posting is not affected and works as expected, so we would need some information regarding the settings enabled on the job and estimate in order to try and duplicate the problem you are experiencing.