naming-factory-dbcp.jar classes not loading

At the risk of inundating this forum with more newbie questions, I have yet another (thanks Ben for all of your help so far).

Once again, I am migrating a simple webapp from Tomcat 4.1 to 5.5.20. One problem I'm having now is at startup--from the catalina log:

SEVERE: Exception processing Global JNDI Resources
javax.naming.NamingException: Could not load resource factory class [Root exception is java.lang.ClassNotFoundException: org/apache/tomcat/dbcp/dbcp/DataSourceConnectionFactory.class]

This problem (among others) is leading (I think) to a "No suitable driver" error in my webapp anytime I have a jsp that needs to get to my database. ( BTW, apparently, the MemoryUserDatabaseFactory class is being loaded just fine, as I'm able to login to my app and such, and there is no error on startup regarding that class.)

Thing is, this class is where it should be, within . And TC is loading other classes from that directory. I suppose it could still be a CLASSPATH problem, but why in the world would this jar not be part of Tomcat's CLASSPATH for loading?

What other reasons for not loading the resource factory class (besides CLASSPATH problems) might I investigate?

Any help would be very much appreciated. Thanks!

Hi Jeff,
can you tell me about solution? if you have it.

thanks

SEVERE: Exception processing Global JNDI Resources
javax.naming.NamingException: Could not load resource factory class [Root exception is java.lang.ClassNotFoundException: org/apache/tomcat/dbcp/dbcp/DataSourceConnectionFactory.class]

This is one of the classes provided by Tomcat.
Did you accidentally move any of the jars from your older version of Tomcat into your newer version (from tomcat/common/lib)?