Diagnosis
In the table TTZCU no time zone is maintained/active
A time stamp (time zone UTC) is also transferred to R/3 with theresults of the APO backorder processing. This time stamp states whenthe backorder processing was started in APO. It must be converted tothe time zone of the application server of the R/3 System so that it ispossible to check if a document was changed or delivered in themeantime.
This is why the time zone must be maintained in the database tableTTZCU (Customizing of time zones.)

Procedure
Call up transaction SM31 and maintain the table/view 'TTZCU'.