pbsdsh: What happened to PBS_VNODE (and other mysteries)

Question

I am trying to figure out how to use pbsdsh. I have a PBS script and a bash script. The PBS script looks like:

#!/bin/bash

## Required PBS Directives --------------------------------------
#PBS -A blahblahblah
#PBS -q debug
#PBS -l select=1:ncpus=32:mpiprocs=2
#PBS -l walltime=00:00:30
#PBS -j oe
#

## Execution Block
# Environment Setup ----------------------------------------------
cd $PBS_O_WORKDIR

pbsdsh -v $PBS_O_WORKDIR/greetings.bash

exit $?

The bash script greetings.bash will hopefully be much more involved very soon, but for now all it has is:

#!/bin/bash
#
#echo ::: $PBS_NODENUM :::  $PBS_VNODENUM :::

exit 0

I submit to PBS and get the output:

::: 0 ::: :::
::: 0 ::: :::
pbsdsh: spawned task 0x00000000 on logical node 0 event 2
pbsdsh: spawned task 0x00000001 on

So, first question: Why does the script find a value for $PBS_NODENUM but $PBS_VNODENUM is undefined?

Here's another question:

In the PBS script, I am cd'ing to $PBS_O_WORKDIR, and then running $PBS_O_WORKDIR/greetings.bash. But then I think, well, I'm already in $PBS_O_WORKDIR, so surely I don't have to specify it again in the pbsdsh command. "./greetings.bash" should be sufficient. Right? So I make that change to the script, and I get no results at all. I get the error messages:

: No such file or directory
: No such file or directory

Why should that happen? BTW, I saw an example with a script with the line PATH=$PBS_O_PATH and I tried inserting that into greetings.bash. No change.