SSRS report viewer log on failed

[nickhyena]

I have set up a web based report viewer using the SSRS reportviewer control (sql server 2008 r2) including the ability to specify credentials.When I comment out the bit that sets the credentials and run the web page the report is displayed.When I set the credentials to something invalid I get "The request failed with HTTP status 401: Unauthorized."When I set the credentials to something valid I get "Log on failed. Ensure the user name and password are correct. (rsLogonFailed)"For the valid credentials I have gone into the SQL Server Reporting Services web page and set up the user security in Site Settings and also set up the secrity in the Folder Settings as discussed in this link HowTo Install SQL Server 2008 R2. One of my valid users is even dbo on the Report Server database.What am I missing?Thanks