Steve,
You're hitting one of those "catch-22" errors while using "maglev-rake".
If you use MRI rake instead, either "rake", "rake status" or "rake invoicing_test:status" you won't get that error and MRI rake should run
"sh "$GEMSTONE/bin/gslist -clv" correctly.
It could be some confusion over which stone for "maglev-rake" to use, or some glitch with environment variables, or something that removed the invoicing_test..LCK file in your $MAGLEV_HOME/locks directory. Hard to speculate without hands on.
-- Monty