Postgres locks table schema?

Hi.

When running SQL scripts, which change the tables' schema, we sometimes experience a lock of these tables' schema. The lock occurs on the first command of the script, on the first modified table. When this occurs, no further schema modification for this table is possible, until the server is restarted, which is very problematic for a production environment.

Perhaps someone is familiar with this behavior, and how it can be resolved, without the restart of the server?

The server used is PostgreSQL 8.0.3, and the OS is Fedora Core 3.

Thanks.

Stas Oskin.