Problems with headers in redirect

Hi, I'm hoping someone can help me with this one... I'm doing redirects to various types of file (Flash, Office, DWF etc) and have found a problem with IE5. I pass the script a document ID, and it retrieves the document record from a database, which stores the location of the file on the web server, and redirects the browser to the document. What happens is that the browser gets redirected, but doesn't get the content-type header, and subsequently can't display the document. Until yesterday I was using javascript redirection, which worked fine. However for other reasons (ie that didn't work with IE 5.5 or IE6) I had to change to using the header("Location: ") way. Only work around I can see is to do the redirection based on browser type (i.e. one way for IE5, the other for IE5.5/IE6) but thats messy. Any other ideas??? Richy