First, double check that your classpath is indeed correct.
Second, try opening the jar and check that it actually contains the org.apache.commons.logging.LogFactory class.
Finally, try debugging by setting a breakpoint in the class loader. !!–Kolibri!!
If you're using maven for managing dependencies, add the following line in your pom.xml:
<dependency>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
<version>1.1.1</version>
</dependency>