I want to compile and make .jar, it was working but now I got this exception
all the time:

C:\>ant
java.lang.InstantiationException: org.apache.tools.ant.Main
at java.lang.Class.newInstance0(Class.java:291)
at java.lang.Class.newInstance(Class.java:259)
at org.apache.tools.ant.launch.Launcher.run(Launcher.java:214)
at org.apache.tools.ant.launch.Launcher.main(Launcher.java:90)