Why does my deployed MATLAB code require and active X-Windows session when being utilized in batch scheduled mode ?

My deployed MATLAB (r2011b version) code requires an active X-Windows session (or legitimate value for $DISPLAY) when deployed in a batch scheduled mode on a linux cluster. If either of these is not available, the rendered graphics is very poor and extremely slow to execute. Is there a compiler flag that can be set to avoid this behavior ? All of the graphics in the code is constructed using figure('Visible','OFF') and then sent to PNG files.