>The TRACE debugger window always reports "Source Not Available". Does anyone know what causes this?

The debugger is unable to locate the source code for what's being debugged. You need the compiled code and the source to be available when you're using the debugger; you can't extract 'decompiled' source code within the deugger if the source files can't be found, or if the time/date stamps between the source and compiled code don't tie out.