Caliper loses track of worker with "Error: Could not find or load main class"

Question

I'm trying to run Caliper, but I got the dreaded benchmark death exception:

java.lang.RuntimeException: Got no response!
  at com.google.caliper.runner.CaliperRun.measure(CaliperRun.java:241)
  at com.google.caliper.runner.CaliperRun.run(CaliperRun.java:132)
  at com.google.caliper.runner.CaliperMain.exitlessMain(CaliperMain.java:88)
  at com.google.caliper.runner.CaliperMain.main(CaliperMain.java:58)
  at com.google.caliper.runner.CaliperMain.main(CaliperMain.java:47)
  at FastBigBenchmark.main(bench.mirah:22)

The errorLog in CaliperRun contains "Error: Could not find or load main class", but doesn't have a stack trace or anything else useful.

As you can tell from the stack trace, I'm using Mirah to generate the benchmark class, but before you suspect Mirah is the problem, here is the javap-decompiled main method generated in my benchmark class:

public static void main(java.lang.String[]);
Code:
   0: ldc           #2                  // class FastBigBenchmark
   2: aload_0       
   3: invokestatic  #36                 // Method com/google/caliper/runner/CaliperMain.main:(Ljava/lang/Class;[Ljava/lang/String;)V
   6: return        

(You can see that this exists in the stack trace, too.)

Any tip on where to start digging to debug this problem? I don't know where this problem might be originating from in Caliper.