How do I make a postback from jQuery UI dialog without getting 404 error

[boobs]

I am trying to make a popup with with a DropDownList and a radioButton(all the controls are inside a div called "casefiles". I set the AutoPostback to true on the radio button so that it will call the radio buttions "CheckedChanged" method and sort the dropdownlist. The DropdownList gets populated with fileID's from a stored procedure.But when I click on the RadioButton I get this error:\[code\]->POST http://localhost:49355/oscidv4/ViewNotes.aspx?CaseFileID=202 404 (Not Found) :49355/oscidv4/ViewNotes.aspx?CaseFileID=202:1Uncaught Sys.WebForms.PageRequestManagerServerErrorException: Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server. The status code returned from the server was: 404Error$createSys$WebForms$PageRequestManager$_createPageRequestManagerServerErrorSys$WebForms$PageRequestManager$_onFormSubmitCompleted(anonymous function)(anonymous function)Sys$Net$WebRequest$completedSys$Net$XMLHttpExecutor._onReadyStateChange\[/code\]This is my javascript/jQuery that builds the popup:\[code\]function getCaseFiles(canMoveExpenses) { //create Popup with content from div $('#casefiles').dialog({ autoOpen: true, height: 'auto', width: 'auto', modal: true, buttons: { "Ok": function () { debugger; alert(2); }, Cancel: function () { $(this).dialog('close'); $("#viewExpensesGrid").flexReload(); } } }); }\[/code\]My code behind doesn't even get called. It just goes straight to that error