Whether that dll is built in debug mode doesn't matter for debugging, in spite of the name! What you need is the .pdb file for that DLL. The .pdb file contains all the references that link the compiled code segments to the original code statements. If you have the .pdb, make sure it's accessible, e. g. in the same directory as the .dll file, or in the directory of your application. If you have that DLL in your solution, includ9ing the source code, you should check your build options and make sure a .pdb is actually built.
GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)