You have to request the output of the concentrated forces (CF) for the step you want the plot...which I think is selected by default.
Then in the visualization module you can create an XY Data based on applied the concentrated force. You have to select the node where CF was applied.
Visualization Module->Tools Menu->XY Data->Create->
Source="Odb field output"
Position="Unique nodal"
Check "CF Point Loads".
Supply the node where the force was applied in the "Elements/Nodes" tab.