sqlzoo.net Problems with the PostgreSQL Interactive Tutorial

I am not sure if anyone is already familiar with this this site.
Andrew Cumming of the School of Computing of Napier University has
developed a very useful turtorial that is an excellent tool for anyone
trying to learn SQL.  The on-line tutorial allows the user to chose
one of the following back-end RDMBS engines ( PostgreSQL | MySQL | MS
SQL Server | DB2 | Oracle ) to test the user entered SQL.

However, it seems that there are problems with the PostgreSQL and MS
SQL Servers back-ends.  The back-end returns various server generated
errors.

I am wondering if the PostgreSQL community would like to offer Andrew
some/any-kind of support for his site to correct any
application/PostgreSQL server errors and at the same time advertise
his site as a reference that newbies coming to PostgreSQL could use
when trying to learning SQL in PostgreSQL.

It would be unfortunate if newbies would discount PostgreSQL for one
of the other RDBMS due to their in-ability to learn SQL using the
PostgreSQL backend.

Here is Andrew's personal info website:
http://www.dcs.napier.ac.uk/~andrew/

Any thoughts?

--
Regards,
Richard Broersma Jr.

Visit the Los Angeles PostgreSQL Users Group (LAPUG)
http://pugs.postgresql.org/lapug