Currently sending additional parameters to the event handler is not supported, however please note that
in the handler you can access the caller by using the "this" keyword:

It's rather atrocious that Telerik still hasn't supported passing additional parameters in the event handler 5 years later - but it turns out that there's a simple workaround, kindly identified by a Sergey T on Stackoverflow, which works well and isn't too fragile:

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I would suggest passing the target grid id as an argument to your function. Example: .Events(events => events.Error("function(args){telerikGridAraxErrorhandler(args,'myGridId');}"))
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In other words, rather than passing a string containing the error handling function name, pass a string containing a closure which is called by the Telerik control, and which in turn calls your event handler with your additional parameter(s), which is 'myGridId' in the above example.  

THANKS PHIL this worked perfectly

Another Thank you Phil - that is SUPER helpful! Thanks again.

For future people that find this - here is the Stackoverflow question/answer:

https://stackoverflow.com/questions/20886651/get-a-reference-to-kendo-grid-from-inside-the-error-handler/28591103#28591103