I'm also facing the same issues. I recently downloaded the jBPM 5.4.0-Final installer (http://sourceforge.net/projects/jbpm/files/jBPM%205/jbpm-5.4.0.Final/jbpm-5.4.0.Final-installer-full.zip/download), ran first ant install.demo and then ant demo.start. Then I went into http://localhost:8080/drools-guvnor/, and I get the page up and running, and a question about if I want to install sample data (or something similar..), I answered yes. No the message "Please wait, Loading application" is flashing against me, not stopping.
Any clue? I will try to reinstall the whole thing once more now, without importing sampe data to see if it makes any difference.