Error message references page on dev box, not server

[Webskater]

Is this normal? I have never noticed it before and can't understand it.

I am developing a web application on a PC. The application files are in C:\Development\myApplication

I publish the site to a test server on a local network. I publish the site to \\mytestServer\WebSites\myApplication

This server address is actually D:\WebSites\myApplication - and, after I publish, all that is in there are are the usual .aspx files and the compiled dll in the bin etc.

Running the site in a browser going to http://mytestserver/myApplication/OutlookReminders.aspx (whose virtual directory is pointing to the physical directory D:\WebSites\myApplication) the site runs okay. However, one page is falling over and the stack trace says the error is in C:\Development\myApplication\OutlookReminders.aspx

Which I don't get. How does the server know where the application was developed? Surely these errors would normally say, in the stack trace, that the error occurred in http://mytestserver/myApplication/OutlookReminders.aspx. Why is it saying the error is in a file on a development box?

Am I going nuts?