Take note of the effects of the program - see long text

What causes this issue?

This program is used to subsequently post planning data to CO objects
in FI-SL.
Bear in mind that there is no way to check whether data already exists
for these objects in FI-SL. If this is the case, the old data is not
deleted and the new data is added.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Be aware of this possibility. If documents do exist for the CO-data
that is to be subsequently posted, you can use the report RGUREC50,
which allows you to check whether the documents have already been
posted to FI-SL.

Error message extract from SAP system. Copyright SAP SE.