What version of Hibernate are you using? If you are using Hibernate 2.1.6 the proxool.xml file will be found in the classpath. Here is what the spring configuration should look like for the Hibernate configuration:
If you are using the hibernate jar that is in the samples you will need to specify the full path. Hope this helps. I am not sure if you altered anything from the original files. This seems to be the case base on the information you gave me.