rrd file not found

[ustabile]

Hi, I have little bit problem. After I have created a Data input method, I created a data source but when I save the rrd file It was not created. I linked the data source to localhost so the device is up, but I don't undestand what is happening. If I create rrd file with shell script the file has been create but It's not update with data. Can somoone why or can help me ?
thanks a lot.