maven - OpenEJB (TomEE+) fails to start with ArithmeticException

Question

I'm using Tomee+ with Maven. I can run locally (Windows XP/7, JDK 1.6, Maven 2.2.1), but running the tests on our Jenkins CI server generates a load of these and hangs:

Running server.util.MessageProcessorTest Exception in thread "Thread-17" Exception in thread "Thread-19" Exception in thread "Thread-14" java.lang.ArithmeticException: divide by zero
...
Exception in thread "Thread-25" java.lang.ArithmeticException: divide by zeroException in thread "Thread-30" java.lang.ArithmeticException: divide by zero
java.lang.ArithmeticException: divide by zero   at org.apache.openejb.Core$3.run(Core.java:118)

I'm using openejb 4.5.1:

<dependency>
        <groupId>org.apache.openejb</groupId>
        <artifactId>openejb-core</artifactId>
        <version>4.5.1</version>
        <scope>test</scope>
</dependency>

The Jenkins CI server is an 80-core Red Hat 4.1.x (Linux 2.6.x) box, running JDK1.6, Maven 2.