Problem in Filter Setting for Customer_Main

Dears,

I am doing filter setting on the Customer_Main obj. in CRM 5.0 and there are 2 tables for which I need to set filter: KNVV and KNVP

When I set the filter agaist KNVV & field VKORG> Its saved and available for use. But when I set the filter against KNVP & field VKORG>its not saved and disappears from the filter. I checked SMOFFILFLD table and the entries are present there. Surprising that the table KNVP is not appearing in f4 of "table/structure" of the filter setting. Any clue if this is a common problem ? What is the way to fix this ?

Same thing I tried for VTWEG (dist channel) for both the tables KNVV and KNVP, it works. Problem shows with VKORG.

Any pointers would be much appreciated.

Thanks a lot

Anjana