Just download Grails, did the configuration, but when i start grails, gives me this error.

Error opening zip file or JAR manifest missing : C:/grails-2.0.1/lib/com.springsource.springloaded/springloaded-core/jars/springloaded-core-1.0.2.jar
Error occurred during initialization of VM agent library failed to init: instrument
C:\grails-2.0.1\bin