In the Source window, you may not be able to obtain a source view of an object if the debugger is finding a different version of the executable than the one you created with debug information. Set the Show module path check box in the Options->Window Settings->Display Style dialog of the Session Control window, so that full pathnames are displayed in the components pane of the Session Control window. Check that the modules listed are in the correct location. If they are not, you can exit the debugger, remove or rename the executable or DLL in the incorrect path so that the one in the correct path is accessed, and start debugging again. (For example, if there is an obsolete version of your executable in one directory, and an updated version in another, and the obsolete directory's entry in PATH precedes that of the updated directory, remove the executable from the obsolete directory.)
You can also specify an absolute path to the version you know was compiled with debug information, when you invoke the debugger or in the Startup dialog. To bring up the Startup dialog, choose File->Startup from within the Source or Session Control window, or start the debugger with no parameters.