Excel 2007 :: Do Loop With IF Statement

I am having an issue getting an IF statement to work inside a DO loop. I have Microsoft Excel 2007 and Windows 7 Entreprise.

In my Excel spreadsheet, I have in column B a list of keywords and in column C the category to which each keyword belongs. For instance, the keyword "boot" goes withe the category "Shoes", "scarf" goes in "Accessories", etc.

In another column, I have a list of product descriptions (like "Black Boots" or "Silk Scarf") and I would like to assign the relevant category to each product. I thought to do this by creating a new function in VBA. This function would go through the whole list of keywords in column B, checking if the keyword is included in the product description. If it is, the function's result would be the relevant category, and if it is not, the function would search the next line in column B, until a relevant keyword is found, or until the end of the list.

Here is the code I have written so far:

Code:
Function SegmentSearch(Item)
Dim i As Integer
i = 1
Do
i = i + 1

If Application.WorksheetFunction.IsNumber(Application.WorksheetFunction.Search(Sheet5.Cells(i, 2), Item)) = "TRUE" Then SegmentSearch = Cells(i, 3)
Loop Until Application.WorksheetFunction.IsNumber(Application.WorksheetFunction.Search(Sheet5.Cells(i, 2), Item)) = "TRUE"
End Function

Without the loop, the function works fine (if "Item" happens to include the first keyword in the list) but as soon as I try putting the loop I get a #VALUE! error.