jQuery Grid Plugin - jqGrid

After days of trying to get this working with the jquery plugin for struts, the best I have come up with is when an error occurs on the server side, I catch the Exception & then I set the status code in my action class. This seems to work to a degree in that the jqgrid will show the error number I set in my action. However, the message I want to display does not get displayed.

so in my action class I have done so:

And now the grid does display the error code 777 but doesnt display the message beside it. I get a an error like:

Anyone know if what I am doing is actually the best way to go about error handling? Or am I doing it completely wrong.

I am fairly new to all this and help is very much appreciated. I have looked at dozens of examples on jqgrid but nothing quite puts it all together especially when dealing with struts.