failure of jdbc dirver

[Steven Dahlin]

I am getting the following error indicating the derby database not found:

2010-05-17 16:30:00,313 [main] ERROR JPOX.RDBMS.Schema  - Failed
initialising database. Please check that your database JDBC driver is
accessible, and the database URL and username/password are correct.
Exception : Cannot create JDBC driver of class '' for connect URL 'null'
org.apache.commons.dbcp.SQLNestedException: Cannot create JDBC driver of
class '' for connect URL 'null'

In trying to get Continuum 1.4.0 up and running on Tomcat 6.  I have set up
the location of the context info needed for the driver in both the
$CATALINA_HOME/conf/Catalina/localhost/continuum.xml and
$CATALINA_HOME/webapps/apache-continuum-1.4.0/META-INF/context.xml
locations.  The file is structured as follows:

<Context path="/apache-continuum-1.4.0"

docBase="${catalina.home}/apache-continuum-1.4.0/apache-continuum-1.4.0.war">
  <Resource name="jdbc/users"
            auth="Container"
            type="javax.sql.DataSource"
            username="sa"
            password=""
            driverClassName="org.apache.derby.jdbc.EmbeddedDriver"
            url="jdbc:derby:database/users;create=true" />
  <Resource name="jdbc/continuum"
            auth="Container"
            type="javax.sql.DataSource"
            username="sa"
            password=""
            driverClassName="org.apache.derby.jdbc.EmbeddedDriver"
            url="jdbc:derby:database/continuum;create=true" />
  <Resource name="mail/Session"
            auth="Container"
            type="javax.mail.Session"
            mail.smtp.host="localhost"/>
</Context>

The derby.jar file is in the /usr/share/lib and
/var/lib/tomcat6/webapps/apache-continuum-1.4.0/WEB-INF/lib directories.  I
have seen various sites indicating solutions but cannot get it to work.

Any suggestions?

Thanks