In the past i had found the similar problem.The problem was appeared because of "toUpperCase();" code.Changing the
uppercase of "i" to "I" is not proper.but changing "i" to "(\u02dc)" is proper.Unfortunately, in your language changing "i" to
"\u02dc" not proper. the source of the problem is my locale.I live in turkey.WindowXP locale turkiye. So I have set up locale to English USA
and problem has been resolved.Effectted components is containing toUpperCase() or lowerCase(). For example :
com.sun.stylesheet.StylesheetException: unable to convert string 'WHITE' to a color
        at com.sun.stylesheet.types.AbstractColorConverter.convertFromString(AbstractColorConverter.java:123)
        at com.sun.stylesheet.javafx.ColorConverter.convertFromString(ColorConverter.java:44)
        at com.sun.stylesheet.types.TypeManager.convertFromString(TypeManager.java:486)
        at com.sun.stylesheet.javafx.PaintConverter.convertFromString$impl(PaintConverter.fx:43)
        at com.sun.stylesheet.javafx.PaintConverter.convertFromString(PaintConverter.fx:31)
        at com.sun.stylesheet.types.TypeManager.convertFromString(TypeManager.java:486)
        at com.sun.stylesheet.styleable.DefaultStyleable.convertPropertyFromString(DefaultStyleable.java:152)
        at com.sun.stylesheet.Declaration.convertValue(Declaration.java:76)
        at com.sun.stylesheet.Declaration.applyTo(Declaration.java:91)
        at com.sun.stylesheet.Rule.applyTo(Rule.java:221)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:277)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:282)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:282)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:282)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:282)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:282)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:282)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:282)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:282)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:257)
        at javafx.scene.Scene.applyStylesheets$impl(Scene.fx:235)
        at javafx.scene.Scene.applyStylesheets(Scene.fx:43)
        at javafx.scene.Scene.userInit$(Scene.fx:220)
        at javafx.scene.Scene.initialize$(Scene.fx:43)
        at simplevideoplayer.Main.javafx$run$(Main.fx:82)
        at simplevideoplayer.Main.javafx$run$(Main.fx:82)