SUMIF function not returning all data

My SUMIF functions are not returning all data.  The result is a partial sum of the data specified in the criteria.  The SUMIF function is summing 4 out of 6 cells.  My SUMIF function is on a separate page from my ranges. My "Range" and "Sum Range" share a worksheet. I copied the data onto a separate worksheet to use in conjunction with the first, which returned an different incorrect result.  This worksheet was converted from Excel 2003. Any advice.

Thanks,

Kewood