splitting up the command inside of the locked region and recompiling jamvm seemed to fix that

this is progress:

*** Semantic Error: You need to modify your classpath, sourcepath, bootclasspath, and/or extdirs setup. Jikes could not find package "java.lang" in: <DLL: Calling JNI method gnu/java/nio/VMChannel.write(ILjava/nio/ByteBuffer;)I>

this means ant 's jamvm is executing jikes just not with the right classpath