Database Integration with ASP.NET

I would like to add markers to a map from a database of long. & lat
pairs. What is the best way to do this using ASP.NET? For example would
it be ok to loop through the data set on the server and print the
required Javascript code for each individual marker, this could result
in a javascript block that could exceed 5000 lines, which I assume will
degrade performance.

I have tried the ASP.NET control written by Bill Pierce but a can't get
it working, I keep getting the following error:

Could not load type 'TestWeb.Global'. (within the Global.aspx file)

Do I need to set anything up on the web server (I've already configured
it as an application). If anyone has successfully implemented this then
I would be interested to hear any advice you have.