ASPX Response.Redirect pdf document

In my aspx page whenever I do a redirect to a pdf document

Response.Redirect

("http://www.pdfdoc.com/documents/doc1.pdf")

I always get a " This file is damaged and could not be repaired" error?

However if I type the above url in my browser address, It opens up properly with no problems???

Any clue as to what is happening here???

when i try it i get 404 error: page can not be found.