I mounted a subsite called agents.
Then I created a new instance of etp called agents-static and mounted it.
I get the following suggesting it isn't working with sub-sites:
Database operation "0or1row" failed (exception NSDB, "Query was not a statement returning rows.")
while executing
"ns_pg_bind 0or1row nsdb0 {
select content_folder__new(:name, :title, '', etp_get_folder_id(:parent_package_id));
}"
Again, this is running tarballs and cvs updates so maybe it is something to do with that.