Error arrise during define distribution rule

hi gurus,

when i defining Distribution rule during this i have got the error.

i have to define Distribution rule for Energy planning. there for i have define 2 segment - 1) Water & 2) Electricity. for that i have created 2 Consumption related 2 GL Accounts.

Error arrises during the sender /receiver entries.

Here i define Cost center as 1705 (Energy) as sender. & for that i have define cost element. also define receiver as cost center group.

Error: enter either single values (from X to Y) or a group?

when i remove the receiver as cost center group the error arrise give below:

Enter values for field business process,WBS Element,Cost object,Cost center,order.

Pls help me.

Than'x

Dhananjay