Thanks for your answer I have tried IMAGETYPE png and IMAGETYPE gif, but I still get the same error:
Exception in thread "main" java.lang.UnknownError: Unable to initialize image. at edu.umn.gis.mapscript.mapscriptJNI.mapObj_draw(Native Method) at edu.umn.gis.mapscript.mapObj.draw(mapObj.java:382) at es.gva.icv.jmapscript.DrawMap.main(DrawMap.java:43) Thanks Luis Conti