I needed to create the schema using SQL. A schema created with the AS400 command CRTLIB does not work. However, you can still copy AS400 artifacts into the schema (Library in AS400 terms) created by SQL.
I also needed to set the following in the ANT updateDatabase task;
defaultschemaname=“PMD1”
databasechangeloglocktablename=“LIQUIBASE_LOCK”
databasechangelogtablename=“LIQUIBASE_CHANGELOG”
I also needed to set the schema on the connection URL;