TransactionRolledBack exception in XTS interoperability tests

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Test set: com.jboss.transaction.txinterop.interop.ATTest
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Tests run: 15, Failures: 0, Errors: 2, Skipped: 0, Time elapsed: 178.09 sec <<< FAILURE!
testAT3_3(com.jboss.transaction.txinterop.interop.ATTest)  Time elapsed: 6.436 sec  <<< ERROR!
com.arjuna.wst.TransactionRolledBackException: null
	at com.arjuna.wst11.stub.CompletionStub.commit(CompletionStub.java:65)
	at com.jboss.transaction.txinterop.interop.ATTestCase.testAT3_3(ATTestCase.java:252)
	at com.jboss.transaction.txinterop.interop.ATTest.testAT3_3(ATTest.java:113)

testAT4_1(com.jboss.transaction.txinterop.interop.ATTest)  Time elapsed: 0.913 sec  <<< ERROR!
com.arjuna.wst.TransactionRolledBackException: null
	at com.arjuna.wst11.stub.CompletionStub.commit(CompletionStub.java:65)
	at com.jboss.transaction.txinterop.interop.ATTestCase.testAT4_1(ATTestCase.java:281)
	at com.jboss.transaction.txinterop.interop.ATTest.testAT4_1(ATTest.java:119)