Error importing oBusinessPartners with DTW 2005.0.16

I can not import BusinessParters with DTW 2005.0.16. For objects like Items ... it works as usual. With oBusinessPartners the Source data is shown empty, resulting in 0 imports and in 0 errors. If I open the dialog "Maintain Interface" to see the field database, it is empty within the oBusinessPartners.

How can I correct this?

Thanks

Franz