There is a bug in cc.BMFontConfiguration:

        if (cc.renderContextType === cc.WEBGL) {
            var scaleW = parseInt(/scaleW=(\d+)/gi.exec(line)[1]);
            if(scaleW > cc.Configuration.getInstance().getMaxTextureSize())
                cc.log("cc.LabelBMFont._parseCommonArguments(): page can't be larger than supported");

            var scaleH = parseInt(/scaleH=(\d+)/gi.exec(line)[1]);
            if(scaleH > cc.Configuration.getInstance().getMaxTextureSize())
                cc.log("cc.LabelBMFont._parseCommonArguments(): page can't be larger than supported");
        }