I have actually tried putting my code in the code-behind and still get the error. I think the error is coming from the following line
var cm=Web.Net.PageMethodRequest.createProxyMethod
I did not create a new project, but instead have tried to upgrade my old project that used the October release.
Is there any documentation that outlines how to properly update your code from the October release to the December release? The way I figured out how to set up my project was to create an new web site and selected the AJAX template to find out where to put all the new .js files and how to set up my web.config.