Module graph not found

Hi,

I want to display a graph:

require("graph").drawLine(g, steps, {
        axes : true,
        gridy : gridyValue,
        y : 50, //offset on screen
        x : 5, //offset on screen
    });

When uploading to RAM from IDE, the code works, the graph is displayed.
When installed as an application from the app loader, I get this error in IDE and the graph is not displayed:

Uncaught Error: Module graph not found
 at line 26 col 20
    require("graph").drawLine(g, steps, {
                   ^
in function "drawGraph" called from line 3 col 15
    drawGraph();
              ^
in function called from system

Thanks
Christian