Error: Invalid JSON when calling method:

Discussion created by shaningesri on Jul 20, 2011
I loaded ESRI's script gp_profile from and then run it in my server with minor revision.  When running the program in my server, the routing path displays on the map correctly, but the Infobox for the Terrain File does not show up as ESRI's sample.  I run FireBug and to try to detect the error message.
The red message shows that
Post  500 Internal Server error
Below there is the error message:
uncaught exception: [Exception... "'Error: Error: Invalid JSON' when calling method: [nsIDOMEventListener::handleEvent]" nsresult: "0x8057001c (NS_ERROR_XPC_JS_THREW_JS_OBJECT)" location: "JS frame :: chrome://firebug/content/spy.js :: callPageHandler :: line 744" data: no]
Does anyone know how to fix it?  Thanks.