[jbosstools-dev] unable to install JBT M3

I just download JBoss Tools m3 nightly build from http://download.jboss.org/jbosstools/builds/nightly/3.1.0.M3/ and try to install it using Eclipse installation wizard: Help > Install New Software and add a local site for installation, but it failed every time with a lots of error messages, like the message below: java.io.FileNotFoundException: /home/fugang/Download/jbt.updatesite/plugins/org.jboss.tools.xulrunner.initializer_1.0.0.GA-N200909080001-H260.jar (No such file or directory) ...... the org.jboss.tools.xulrunner.initializer_1.0.0.GA-N200909080001-H260.jar is really not there but org.jboss.tools.xulrunner.initializer_1.0.0.GA-N200909080001-H260.jar.pack.gz is there any wrong with the steps of installing JBT from a local update site? Thanks Denny