prob regarding update rules

Hello BW gurus

i m creating a cube same str of 0sd_c03.for this i have 7 datsources.2lis_11_vahdr

, 2lis_11_vaitm,

2lis_11_v_itm

,2lis_12_vcitm,

2lis_12_vchdr,

2lis_13_vdhdr,

2lis_13_vditm.

There is one field in cube" gross weight in Kilogram" but in the datasource field its only "gross weight" not in kilograms.

when i m applying update rules for this key fig its saying "source currency and target currency gross weight must b same".and update rules are not activating.

can anybody tell me how can i solve this problem.