Sometimes the application edit report will need to be rerun before applications can be posted. The error message you get is "The system indicates that you must rerun the Application Edit Report. If the report displays errors, please correct them and run the report again."
This might happen if there are multiple program officers creating grants and running the edit and posting report to review. You ran your Edit report and were examining it, but while you had yours open, someone else ran an Edit report. Theirs is the latest one run and it has priority.
Rerun your error free Edit report and this time you can usually post. When you rerun yours, yours is the latest one run and you should be able to post since this one now has priority.