Source cannot be found - step through disassembly
<p>I have an ASP.NET web app. I reference an external .dll, made by another team member.</p>

<p>When first stepping through my code (which calls this dll's class and method), I get an error (runtime of course) stating that the source cannot be found and if I want to step through disassembly.</p>

<p>What causes this? Also, is it possible to add .pdb files to a project's references?</p>

<p>Thanks </p>
