two corrections

• This isn't what I thought it was. I wasn't including a .dll as a reference. The .dll in question (Castle.Core.dll) was sitting in my bin folder and would "work" when run locally because it was only ever used by a different .dll, but did not end up copied elsewhere when I tried to publish my web app to a folder somewhere because it was not a reference. My problem didn't have to do with the GAC.
• It was pointed out to me today that the reason I cannot send mail via code from outside of my own hosting here is because I am not authenticating. Duh.