Cannot load JDBC driver class 'net.sourceforge.jtds.jdbc.Driver'

I have some problems with jtds.

I am using Hibernate, Tomcat 5.5 on Linux Red Hat Server, SQL Server 2005 with WIndows Server

I save the library in Web-iNF / lib and I am using jtds-1.2.2

I got an error message

16: 56: 17,561 JDBCExceptionReporter ERROR: 78 - Cannot load the JDBC driver class 'net.sourceforge.jtds.jdbc.Driver'

Can someone explain what I'm doing wrong?

Here is the definition of the connection.

<Resource name="pr/jdbc/dsConn" auth="Container" type="javax.sql.DataSource" maxActive="100" maxIdle="30" maxWait="10000" username="example" password="test1234" driverClassName="net.sourceforge.jtds.jdbc.Driver" url="jdbc:jtds:sqlserver://localhost:1433/example" /> 

Can someone help me with this problem?

Regards