When running latest (1.2018.8) plantuml on a file that just contains one of the AsciiMath examples, it shows error java.lang.ClassNotFoundException: org.scilab.forge.jlatexmath.TeXFormula. I din't download the JLatexMath jars because they're not needed for AsciiMath according to the documentation. It still creates an output, but the formula is just rendered plaintext, with math syntax removed.
The complete stack trace is:
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at net.sourceforge.plantuml.math.TeXIconBuilder.<init>(TeXIconBuilder.java:53)
at net.sourceforge.plantuml.math.LatexBuilder.buildIcon(LatexBuilder.java:66)
at net.sourceforge.plantuml.math.LatexBuilder.getImage(LatexBuilder.java:82)
at net.sourceforge.plantuml.math.AsciiMath.getImage(AsciiMath.java:106)
at net.sourceforge.plantuml.math.ScientificEquationSafe.getImage(ScientificEquationSafe.java:112)
at net.sourceforge.plantuml.creole.AtomMath.drawU(AtomMath.java:98)
at net.sourceforge.plantuml.creole.SheetBlock1.drawU(SheetBlock1.java:170)
at net.sourceforge.plantuml.creole.SheetBlock2.drawU(SheetBlock2.java:77)
at net.sourceforge.plantuml.svek.image.Opale.drawU(Opale.java:128)
at net.sourceforge.plantuml.activitydiagram3.ftile.vcompact.FtileWithNoteOpale.drawU(FtileWithNoteOpale.java:197)
at net.sourceforge.plantuml.activitydiagram3.ftile.UGraphicInterceptorUDrawable2.draw(UGraphicInterceptorUDrawable2.java:67)
at net.sourceforge.plantuml.activitydiagram3.ftile.FtileAssemblySimple.drawU(FtileAssemblySimple.java:113)
at net.sourceforge.plantuml.activitydiagram3.ftile.FtileWithConnection.drawU(FtileWithConnection.java:72)
at net.sourceforge.plantuml.activitydiagram3.ftile.TextBlockInterceptorUDrawable.drawU(TextBlockInterceptorUDrawable.java:56)
at net.sourceforge.plantuml.activitydiagram3.ftile.Swimlanes.drawU(Swimlanes.java:191)
at net.sourceforge.plantuml.graphic.TextBlockCompressed.drawU(TextBlockCompressed.java:59)
at net.sourceforge.plantuml.graphic.TextBlockRecentred.drawU(TextBlockRecentred.java:57)
at net.sourceforge.plantuml.ugraphic.ImageBuilder.writeImageInternal(ImageBuilder.java:254)
at net.sourceforge.plantuml.ugraphic.ImageBuilder.writeImageTOBEMOVED(ImageBuilder.java:178)
at net.sourceforge.plantuml.activitydiagram3.ActivityDiagram3.exportDiagramInternal(ActivityDiagram3.java:210)
at net.sourceforge.plantuml.UmlDiagram.exportDiagramNow(UmlDiagram.java:224)
at net.sourceforge.plantuml.AbstractPSystem.exportDiagram(AbstractPSystem.java:135)
at net.sourceforge.plantuml.PSystemUtils.exportDiagramsActivityDiagram3(PSystemUtils.java:179)
at net.sourceforge.plantuml.PSystemUtils.exportDiagrams(PSystemUtils.java:98)
at net.sourceforge.plantuml.SourceFileReaderAbstract.getGeneratedImages(SourceFileReaderAbstract.java:153)
at net.sourceforge.plantuml.Run.manageFileInternal(Run.java:450)
at net.sourceforge.plantuml.Run.processArgs(Run.java:361)
at net.sourceforge.plantuml.Run.manageAllFiles(Run.java:331)
at net.sourceforge.plantuml.Run.main(Run.java:179)