Macでec2-tools使うと時々Javaがゲロ吐く件

sleepモード復旧時にec2-***コマンド使うと１回目は必ずエラーになるんですよ。
二回目以降は問題なく実行できる。
なんすかねこれ。

Unexpected error:
org.codehaus.xfire.XFireRuntimeException: Couldn't load DatatypeFactory.. Nested exception is javax.xml.datatype.DatatypeConfigurationException: Provider org.apache.xerces.jaxp.datatype.DatatypeFactoryImpl not found
javax.xml.datatype.DatatypeConfigurationException: Provider org.apache.xerces.jaxp.datatype.DatatypeFactoryImpl not found
	at javax.xml.datatype.DatatypeFactory.newInstance(DatatypeFactory.java:137)
	at org.codehaus.xfire.aegis.type.java5.DurationType.<init>(DurationType.java:25)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
	at java.lang.Class.newInstance0(Class.java:355)
	at java.lang.Class.newInstance(Class.java:308)
	at org.codehaus.xfire.aegis.type.DefaultTypeMappingRegistry.registerIfAvailable(DefaultTypeMappingRegistry.java:434)
	at org.codehaus.xfire.aegis.type.DefaultTypeMappingRegistry.createDefaultMappings(DefaultTypeMappingRegistry.java:414)
	at org.codehaus.xfire.aegis.type.DefaultTypeMappingRegistry.createDefaultMappings(DefaultTypeMappingRegistry.java:311)
	at org.codehaus.xfire.aegis.type.DefaultTypeMappingRegistry.<init>(DefaultTypeMappingRegistry.java:131)
	at org.codehaus.xfire.aegis.type.DefaultTypeMappingRegistry.<init>(DefaultTypeMappingRegistry.java:137)
	at org.codehaus.xfire.aegis.type.DefaultTypeMappingRegistry.<init>(DefaultTypeMappingRegistry.java:118)
	at org.codehaus.xfire.jaxb2.JaxbTypeRegistry.<init>(JaxbTypeRegistry.java:15)
	at com.amazonaws.ec2.doc._2012_03_01.AmazonEC2Client.create0(AmazonEC2Client.java:57)
	at com.amazonaws.ec2.doc._2012_03_01.AmazonEC2Client.<init>(AmazonEC2Client.java:26)
	at com.amazon.aes.webservices.client.Jec2Impl.setupClient(Jec2Impl.java:175)
	at com.amazon.aes.webservices.client.Jec2Impl.<init>(Jec2Impl.java:171)
	at com.amazon.aes.webservices.client.cmd.BaseCmd.invoke(BaseCmd.java:918)
	at com.amazon.aes.webservices.client.cmd.AuthorizeGroup.main(AuthorizeGroup.java:41)
Caused by: java.lang.ClassNotFoundException
	at javax.xml.datatype.FactoryFinder.getProviderClass(FactoryFinder.java:108)
	at javax.xml.datatype.FactoryFinder.newInstance(FactoryFinder.java:146)
	at javax.xml.datatype.FactoryFinder.findJarServiceProvider(FactoryFinder.java:298)
	at javax.xml.datatype.FactoryFinder.find(FactoryFinder.java:223)
	at javax.xml.datatype.DatatypeFactory.newInstance(DatatypeFactory.java:131)
	... 20 more