jmap fails with exception 'field "_size" not found in type ThreadLocalAllocBuffer'

jmap is unable to extract a heap dump file from a core file with the following exception:

java.lang.RuntimeException: field "_size" not found in type ThreadLocalAllocBuffer

Below is the full stack:

$ /net/gtee.sfbay/export/gtee/results/MUSTANG/NIGHTLY/VM-MAIN/JDK/baseline/solaris-i586/bin/jmap -dump:format=b,file=heap.bin /net/gtee.sfbay/export/gtee/results/MUSTANG/NIGHTLY/VM-MAIN/JDK/baseline/solaris-i586/bin/java core
Attaching to core core from executable /net/gtee.sfbay/export/gtee/results/MUSTANG/NIGHTLY/VM-MAIN/JDK/baseline/solaris-i586/bin/java, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 20061122112410.ik199011.rt_merge
Dumping heap to heap.bin ...
Exception in thread "main" java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at sun.tools.jmap.JMap.runTool(JMap.java:178)
        at sun.tools.jmap.JMap.main(JMap.java:110)
Caused by: java.lang.ExceptionInInitializerError
        at sun.jvm.hotspot.runtime.Thread.tlab(Thread.java:98)
        at sun.jvm.hotspot.oops.ObjectHeap.collectLiveRegions(ObjectHeap.java:526)
        at sun.jvm.hotspot.oops.ObjectHeap.iterate(ObjectHeap.java:226)
        at sun.jvm.hotspot.utilities.AbstractHeapGraphWriter.write(AbstractHeapGraphWriter.java:34)
        at sun.jvm.hotspot.utilities.HeapHprofBinWriter.write(HeapHprofBinWriter.java:399)
        at sun.jvm.hotspot.tools.HeapDumper.run(HeapDumper.java:39)
        at sun.jvm.hotspot.tools.Tool.start(Tool.java:204)
        at sun.jvm.hotspot.tools.HeapDumper.main(HeapDumper.java:60)
        ... 6 more
Caused by: java.lang.RuntimeException: field "_size" not found in type ThreadLocalAllocBuffer
        at sun.jvm.hotspot.types.basic.BasicType.getField(BasicType.java:166)
        at sun.jvm.hotspot.types.basic.BasicType.getField(BasicType.java:173)
        at sun.jvm.hotspot.types.basic.BasicType.getField(BasicType.java:177)
        at sun.jvm.hotspot.types.basic.BasicType.getCIntegerField(BasicType.java:240)
        at sun.jvm.hotspot.runtime.ThreadLocalAllocBuffer.initialize(ThreadLocalAllocBuffer.java:41)
        at sun.jvm.hotspot.runtime.ThreadLocalAllocBuffer.access$000(ThreadLocalAllocBuffer.java:21)
        at sun.jvm.hotspot.runtime.ThreadLocalAllocBuffer$1.update(ThreadLocalAllocBuffer.java:30)
        at sun.jvm.hotspot.runtime.VM.registerVMInitializedObserver(VM.java:330)
        at sun.jvm.hotspot.runtime.ThreadLocalAllocBuffer.<clinit>(ThreadLocalAllocBuffer.java:28)
        ... 14 more
$