Excel 2007, Multiplying Vlookup??

[superfly28]

Hi guys have a strange problem I have 2 worksheets the first worksheet has 3 applicable columns, and the second worksheet is simply to hold data.

The first applicable column is the number range data validation for every cell in that column, which 6,8,10,12,16,20,25,32,40,50 the data validation is hidden in the second work book and the code: =Specification!B15:B25

This then depending on which number selected feeds a different answer to the second applicable column.

the second applicable column on worksheet 1 is a vlookup which has the code
=VLOOKUP(E10,Specification!$I$15:$J$24,2,0)

This also works fine then in the next column I want to multiply the third applicable column which can be any number self inputted from 1to100 so I have done a simple equation =R10*H10, I have tried this with =sum(

and I get results for numbers 6,12,16,20,50, I don't get a #VALUE! error for the number 8,10,25,32,40

I do hope someone can shed some help,

Thanks in advance