back order processing

well im trying to do back order processing and getting the following problem can u please help me

like my sales oder is confirmed for 4 qty ......

by v_ra i wnt to chage it to only 1 when i do this im getting the order in the list ..when im selcting it and clicking on backorders system is throwing an error mesage " <i>check settings for cheking group 02 and cheking rule</i> "

prior to this when i try to amintian a cheking rule for my plant in OMIH

i cannot see my plant nither ther is a newentry button ............

well how to solve this ........help me in solving this

thanks & regards