Excel 2008 : SUMIF using Name and Date Range criteria

Attempting to create a form sheet that compares the sums of several employees' sales in specific categories, between two different date ranges. When the 'Start Date' and 'End Date' on the top of either Range are adjusted, data in the categories should change.

The specific snag I am encountering, is finding a SUMIFS statement whose criteria are Name, and Date Range. I have considered using DSUM as an alternate function, but the layout of my 'Display' sheet prohibits it.

Specifics are as follows:

• The 'Tracker Entry Form' sheet houses all of the data entered from each employee's tracker. Name is Column A, Date is Column B, and the specific sales category I am tracking is in Column D.

• The 'Date-Rage Comparison' sheet is where my formulas should be, in cell C10. Name is Column A on this sheet as well. End Date is stored in cell G5, and Start Date in C5. The formula I am working on is regarding employee whose name is stored in A10.

The formula I am using, which returns a #VALUE! error, is:
=SUMIFS('Tracker Entry Form'!D:D,'Tracker Entry Form'!B:B,"<="&G5,'Tracker Entry Form'!A:A,A10)-SUMIFS('Tracker Entry Form'!D:D,'Tracker Entry Form'!B:B,"<"&C5,'Tracker Entry Form'!A:A,A10)

Any help on this is GREATLY appreciated, I am stuck and frustrated beyond belief. Thank you all!