Where is the dll that is being compiled form the .cs file  being deployed, to the
bin directory or the GAC? If to the bin directory make sure that you put the
.pdb file in that directory also. The .PDB file contains the symbols that are
necessary for tracing. Also, make sure you are compiling the .cs as a debug
version and not a release version or you won't be able to step through the code.

If you are deploying to the GAC then it becomes more of a problem.

It is deployed in the GAC. Both the dll and .PDb are also under my under my
project bin/debug folder. I use stsdev  to create the poject initially and I am
using DebugBuild when I try to step through. It is never hitting the break
point.

I assume you are using Visual Studio 2005 or earlier. It tends to have problems
finding the PDB when its in the project  but the .dll is in the GAC. Take a look
at the following BLOG entry and see if it doesn't fix your problem.

www.elumenotion.com/.../Post.aspx?ID=23

The article here helps a lot, however it has not still solved my problem From
the module window I see the Dll but under the symbol status it shows that no
Symbol added . So I right clicked at the dll and chose load symbol and I give it
the pdb file  under my debug folder  and it says the Symbol file .PDb does not
match the module. I think somewhere in the link I read that someone has exactly
the same message.

I finally got it resolved. I think the issue was with the tool I am
using stsedv to create the dll . it does not create the PDB file  with
DebugInstall which I use for creating the dll to be loaded  in the Assembly but
when I use DebugBuild for debugging  the first dll and the pdb file it created
will not match the one which later got created with DebugInstall so they don't
match. So what I did is I copied the dll created with DebugBuild and place it in
the assemly and the pdb file in my debug folder  got loaded automatically.