Run QB server. Run QB builder agent on another machine (I tested on two different ones)
Steps
1. Create test configuration
2. Create first step
Name build
Type Shell/Batch Command
Execute Condition If all previous sibling steps are successful
Node Selection On the same node running parent step (on server if no parent)
Command cmd /c echo echo build started > build.cmd
Wait For Finish yes
3. Create second step
Name run-on-node
Type Shell/Batch Command
Execute Condition If all previous sibling steps are successful
Node Selection On specified build agent
Build Agent NEAN2:8811
Command build.cmd
Fetch Input Files
Files To Transfer build.cmd
4. Run the configuration

Build fails with error
21:15:08,708 [master>run-on-node@NEAN2:8811] ERROR - Step 'run-on-node' is failed.
    java.lang.RuntimeException: java.io.IOException: Cannot run program "build.cmd" (in directory "D:\Program Files\QBuildAgent\workspace\root\test-nodes"): CreateProcess error=2, ?? ??????? ????? ????????? ????
        at com.pmease.quickbuild.execution.CommandExecutor.runAndGetResult(CommandExecutor.java:215)
        at com.pmease.quickbuild.plugin.basis.CommandBuildStep.run(CommandBuildStep.java:228)
        at com.pmease.quickbuild.plugin.basis.CommandBuildStep$$EnhancerByCGLIB$$68f44831.CGLIB$run$11(<generated>)
        at com.pmease.quickbuild.plugin.basis.CommandBuildStep$$EnhancerByCGLIB$$68f44831$$FastClassByCGLIB$$c5bbde35.invoke(<generated>)
        at net.sf.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:215)
        at com.pmease.quickbuild.DefaultScriptEngine$Interpolator.intercept(DefaultScriptEngine.java:271)
        at com.pmease.quickbuild.plugin.basis.CommandBuildStep$$EnhancerByCGLIB$$68f44831.run(<generated>)
        at com.pmease.quickbuild.stepsupport.Step.execute(Step.java:449)
        at com.pmease.quickbuild.stepsupport.StepJob.execute(StepJob.java:34)
        at com.pmease.quickbuild.grid.GridJob.run(GridJob.java:120)
        at java.lang.Thread.run(Unknown Source)
    Caused by: java.io.IOException: Cannot run program "build.cmd" (in directory "D:\Program Files\QBuildAgent\workspace\root\test-nodes"): CreateProcess error=2, ?? ??????? ????? ????????? ????
        at java.lang.ProcessBuilder.start(Unknown Source)
        at com.pmease.quickbuild.execution.CommandExecutor.runAndGetResult(CommandExecutor.java:213)
        ... 10 more
    Caused by: java.io.IOException: CreateProcess error=2, ?? ??????? ????? ????????? ????
        at java.lang.ProcessImpl.create(Native Method)
        at java.lang.ProcessImpl.<init>(Unknown Source)
        at java.lang.ProcessImpl.start(Unknown Source)
        ... 12 more

if second step (see step 3) Command change to "${configuration.getWorkspaceDir()}\build.cmd" (without quotes) build succeeds
21:15:30,352 [master>run-on-node@NEAN2:8811] INFO - Running step...
21:15:30,356 [master>run-on-node@NEAN2:8811] DEBUG - Executing command: D:\Program Files\QBuildAgent\workspace\root\test-nodes\build.cmd
21:15:30,356 [master>run-on-node@NEAN2:8811] DEBUG - Command working directory: D:\Program Files\QBuildAgent\workspace\root\test-nodes
21:15:30,419 [master>run-on-node@NEAN2:8811] INFO -
21:15:30,420 [master>run-on-node@NEAN2:8811] INFO - D:\Program Files\QBuildAgent\workspace\root\test-nodes>echo build started
21:15:30,421 [master>run-on-node@NEAN2:8811] INFO - build started
21:15:30,428 [master>run-on-node@NEAN2:8811] INFO - Executing post-execute script...

Error log message "in directory "D:\Program Files\QBuildAgent\workspace\root\test-nodes"" points to me that it is the current directory for run build.cmd, but as for the fact it is not?