You should always include the list in your replies - other people might be interested in the solution.
Oops, thought I had.
There must be at least two transactions involved to create a locking problem like you describe. But since CREATE INDEX takes strong locks, it can easily get locked by other "harmless" things.
OK, I've reduced the calls to CREATE INDEX, waiting to test that. If there's still an issue I will use CONCURRENTLY as you suggested.
