Diagnosis
The entries in the table for this derivation rule have different "From"dates, but in Customizing you specified that the entries should not bedefined with validity dates.
This state is inconsistent and should not occur. One reason for itsoccurrence might be that entries were made directly in the table usinga user-created program and this program does not function correctly.

Procedure
In Customizing, allow entries with validity dates for this derivationrule.
If the entries were made directly in the table by a program, correctthat program.