#REF! error issue

Hi
Dont know why, but I get #REF! error. Enter this formula on a blanc sheet, say in A1

=SUM(OFFSET($B$1,5,0,0,5))

Actually the numbers in OFFSET formula are output of other formulas. As the result it MUST sum B6:F6 range... but it doesn't.... Gotta say that I understand OFFSET function but not in this case

Your range is 0 rows high.

I always say u'r masterful....
Thx great...