'Sys.Net._webmethod._invoke' is null

 I have a .NET website and I was using Microsoft Extensions for a while (v1.something) and have switched to System.Web... (v3.5.0.0).  I have an independant webservice (FACSWS()) and a shelled webservice (ShellService()) and I use the shell one to call the real one in AJAX.  Right now, all I am getting is 'Sys.Net._webmethod._invoke' is null.  I do not know enough to know what would cause that.  I was getting an error before that ShellService() does not exist.  So I changed the "using System.Web.Script.Services;" to "using Microsoft.Web.Script.Services;".  Now, it says that ShellService() exists but Sys.Net._webmethod._invoke' does not.  The *.Web.Script.Services class is used to mark methods as [ScriptService].  It's all in C#.  What would make this happen?
 Thanks,
-Seth

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