"Failed to open a rowset", help needed urgently,please

Question

Hello, My application is a web-based and I have developed a report but when I run it, it keeps giving me "Failed to open a rowset", why? I did have .rpt file where I specified the table to load data from. I also had Crystalreportviewer on my .aspx file and I did bind the cr.viewer to a report document which pointed to the same table in my .rpt file. I also had the syntax crystalviewer.DataBind(); on page load in the .aspx.cs file. The thing is that when the page is loaded, the previous statement "Failed to..." is displayed Secondly, I am sending emails using C# from my host. the host in connected to a local area network in a college. what should be the source of the email. should it be something like: _MM.From="Localhost"; ? Thanx