Language key not defined (CIF)

Hi experts,

currently we get an error message "Language key not defined" during the transfer of a customer from ERP to EWM (CIF - CFM1/CFM2).

Therefore no business partner in EWM is created. I read something about "One-time account" (1957563 and 1975421).

But we also have the problem for non "One-time account" customer.

How can I solve this problem?

Thanks!

Ralf