Sum function returning incorrect results

I have a table of values that is being summed using SQL server 2005 that is returning an incorrect value and I can't figure out why.  I have enclosed the raw values and the total should be 30869.025 (if calced in Excel) and what is being returned using the sum function in SQL is 370428.3!  Any help or guidance you could provide would be much appreciated.

Data file:  http://sdrv.ms/Z84SQp