Page redirect problem

I am using the following code to re-direct a page.

Dim strfile As String = "http://S4"; &
Me.dgResults.DataKeys(e.Item.ItemIndex)
Response.Redirect(Server.UrlPathEncode(strfile))

where Me.dgResults.DataKeys(e.Item.ItemIndex) produces a string such
as:
/olp/audit/current/A010-311005-fhf-01.doc - i.e. to download a Word
document

This code works fine until I reach a document name which has a
"special" character in it such as A010#0704-311005-fhf-01.doc

Does anyone have an idea how I can get around this problem?

.