I got this error trying to debug in VS 2003 on a web project

error while trying to run project: unable to start debugging on the web server. the project is not configured to be debugged.

Basically, I had to go into IIS and add DEBUG to the allowed verbs for .asmx and .aspx files.

inetmgr

->

home directory tab

->

configuration button

->

choose asmx

choose 'all' or add DEBUG to the limit to: field.