[Self hosted] Dashboard no data

On our self hosted server, we have setup our master server as the dashboard server and receiving counter data from game servers. The counter publisher on game servers (as well as the master server itself) has been publishing data to the dashboard service without exception. But one problem we're facing is, on the dashboard webpage, we're unable to see any graph.

What setup I might be missing? (from the log we can see that the dashboard service is receiving and processing data from other machines)

And recent days we're starting to face another issue as shown in the log below:

2015-01-21 13:27:46,343 [3] ERROR Photon.Dashboard.PhontonDashboardService [(null)] - System.IO.IOException: 文件存在。(this means File already exists)

在 System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
在 System.IO.__Error.WinIOError()
在 System.IO.Path.GetTempFileName()
在 Photon.Dashboard.Graphing.PhotonCounterController.GetDashboardImage(String path, NameValueCollection queryString, Byte[]& resultData) 位置 h:\svncontent\photon-socketserver-sdk_3.4\src\Photon.Dashboard\Graphing\PhotonCounterController.cs:行号 237
在 Photon.Dashboard.Graphing.PhotonCounterController.TryGetImage(String path, NameValueCollection queryString, Byte[]& data, String& msg) 位置 h:\svncontent\photon-socketserver-sdk_3.4\src\Photon.Dashboard\Graphing\PhotonCounterController.cs:行号 60
在 Photon.Dashboard.PhontonDashboardService.ProcessImageRequest(String localPath, HttpListenerContext context) 位置 h:\svncontent\photon-socketserver-sdk_3.4\src\Photon.Dashboard\PhontonDashboardService.cs:行号 369
在 Photon.Dashboard.PhontonDashboardService.HttpListenerCallBack(IAsyncResult result) 位置 h:\svncontent\photon-socketserver-sdk_3.4\src\Photon.Dashboard\PhontonDashboardService.cs:行号 233

P.S. is there any where we can download dashboard source code for our own customization? We really want a feature that the dashboard can shown the peak CCU for each day, and all performance data at the peak CCU time point.