I need some help to resolve the above error msg in the window 7 machine. Below is the error appear when i try to generate the file

Found 4 models. Inspecting model relations.

1/4 [=======>--------------------] 25% 2/4 [==============>-------------] 50% 3/4 [=====================>------] 75% 4/4 [============================] 100% In Graph.php line 375:

An error occurred while creating the graph; GraphViz returned: 'dot' is not recognized as an internal or external command, operable program or batch file.