Systemerror 39 Error accessing external object property itemcode

Systemerror 39 Error accessing external object property itemcode at line 270 in function of_transfer of object ue_reservation (or this error in line between 250 and 350)

In this case Beas call a SAP DI-API function, which is available only in SAP 9.1 or higher.

Reason:
- SAP B1 - Version too old
- Wrong DI-API-Version installed

 Solution:

Install correct SAP B1 - Version and DI-API

Related to function "Allocation"