I downloaded grails-1.3.7 and when i run grails help i get the following error

C:\grails-1.3.7>grails help
Welcome to Grails 1.3.7 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: C:\grails-1.3.7

Base Directory: C:\grails-1.3.7
Resolving dependencies...
Dependencies resolved in 1265ms.
Error executing script Help: org.apache.tools.ant.helper.AntXMLContext.setCurre n
tTargets(Ljava/util/MapV
java.lang.NoSuchMethodError: org.apache.tools.ant.helper.AntXMLContext.setCurre n
tTargets(Ljava/util/MapV
at groovy.util.AntBuilder.<init>(AntBuilder.java:91)
at groovy.util.AntBuilder.<init>(AntBuilder.java:73)
at groovy.util.AntBuilder.<init>(AntBuilder.java:69)
at org.codehaus.gant.GantBuilder.<init>(GantBuilder.j ava:39)
at sun.reflect.NativeConstructorAccessorImpl.newInsta nce0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInsta nce(NativeConstruct
orAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newI nstance(DelegatingC
onstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Construc tor.java:494)
at org.codehaus.groovy.reflection.CachedConstructor.i nvoke(CachedConstru
ctor.java:77)
....................................
....................................
at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Native MethodAccessorImpl.
java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(De legatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.codehaus.groovy.grails.cli.support.GrailsStart er.rootLoader(Grail
sStarter.java:234)
at org.codehaus.groovy.grails.cli.support.GrailsStart er.main(GrailsStart
er.java:262)
Error executing script Help: org.apache.tools.ant.helper.AntXMLContext.setCurre n
tTargets(Ljava/util/MapV


Can someone help me to get out of this?

Thanks,
Bibin