While trying to mass import some FTP'd files to a media library I ran into an issue I've never encountered before.

When trying to perform a mass action (either on all or selected files) the asyc postback returns an error of:

"Syntax error: Missing operand after 'filename'' operator."

where "filename" is that name of any give file. I tracked the source of the message (not the error) to the MicrosoftAjaxWebForms.debug.js file in the function

function Sys$WebForms$PageRequestManager$_endPostBack(error, executor, data) {
        if (this._request === executor.get_webRequest()) {
            this._processingRequest = false;
            this._additionalInput = null;
            this._request = null;
        }
        var handler = this._get_eventHandlerList().getHandler("endRequest");
        var errorHandled = false;
        if (handler) {
            var eventArgs = new Sys.WebForms.EndRequestEventArgs(error, data ? data.dataItems : {}, executor);
            handler(this, eventArgs);
            errorHandled = eventArgs.get_errorHandled();
        }
        if (error && !errorHandled) {
            throw error;
        }
    }

I've confirmed this error under multiple browsers (IE, FF, Safari, Chrome) and on multiple servers. This is strange because this was working in the past. Manipulating the files individually still works but is cumbersome for large media needs.

I am running the latest hotfix for 5.5 R2.

Hope this can be corrected soon. Thanks!