Derby database problems when working with MyEclipse,help!!

When i use Derby with MyEclipse,there is some problems,as following:
   Caused by: java.lang.SecurityException: class
"org.objectweb.asm.CodeVisitor"'s signer information does not match
signer information of other cl***** in the same package
        at java.lang.ClassLoader.checkCerts(Unknown Source)
        at java.lang.ClassLoader.preDefineClass(Unknown Source)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
        at
org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:
1817)
        at
org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:
872)
        at
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:
1325)
        at
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:
1204)
        at java.lang.ClassLoader.loadClassInternal(Unknown Source)
        at net.sf.cglib.core.KeyFactory
$Generator.generateClass(KeyFactory.java:165)
        at
net.sf.cglib.core.DefaultGeneratorStrategy.generate(DefaultGeneratorStrategy.java:
25)
        at
net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:
216)
        at net.sf.cglib.core.KeyFactory
$Generator.create(KeyFactory.java:145)
        at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:117)
        at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:108)
        at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:104)
        at net.sf.cglib.proxy.Enhancer.<clinit>(Enhancer.java:69)
        ... 48 more

Could you help me with that?I didn't get any idea about that
SecurityException.
Thanks a lot in advance!