fnReloadAjax

ztl

hi, I am using jsTree and dataTable to show some of my data.
and I want this to happen:
when I select a node on jsTree, my dataTable changes accrroding to its id (I search my server for its data and returns in json).
but firefox tells me that fnReloadAjax is not a function.
I looked up the forum and know that fnReloadAjax can only(?) be called when document is ready.
but I have to configure jsTree like this:
tree(function(){
callback:function(){
table.fnReloadAjax('someurl')
}}

I don't know if I've point it out clearly.
can anyone help me ? please^^
thanks!