Comparing to what you may have been accustom to from previous years (before 2009), the sources have moved and are currently located in cvs under OnlTools/OnlinePlots/.
For development, you should be in the 'dev' environment to build the online plots (run stardev).
You may also need to edit some of the variables in the .rootrc file CompileOnlinePlots.csh generates (the default values may work). For detailed information about the arguments in EvpPlotServer.C, see Expert Modes.
For normal testing against an old run, in EvpPlotServer.C just edit the line after the "-path" option in argsS[] to specify either a run number in /a/ (when on the evp.starp machine) or a daq file (commonly found under /star/data03 on RCAS). Then uncomment the evpServerMain::main line.
You may want to make a copy of this file for running the presenter (a common practice is to make one copy named server.C, and one copy named presenter.C). Just make sure that evpServerMain::main is commented out and evpMainPresenter::main is in.
Starting the server should be done with
root4starN -b -q EvpPlotServer.C
If developing code, recompilation is achieved simply by using cons.
Know what you are doing.
Especially, if you use the evpops account on the evp.starp machine. You might disturb experiment operations.