Unable to install VPE on MacOSX 10.5 64bit

It is not possible to install VPE on MacOSX 10.5 64bit. However instalation works on Win7 64bit where xulrunner is not available as well.

Instalation is failing due to following unsatisfied requirement:

Cannot complete the install because one or more required items could not be found.
Software being installed: JBoss Tools RichFaces 3.2.0.v20101206-2100-H28-Beta2 (org.jboss.tools.richfaces.feature.feature.group 3.2.0.v20101206-2100-H28-Beta2)
Missing requirement for filter properties ~= $0: XULRunner 1.9.12.v20101206-2100-H28-Beta2 (org.jboss.tools.xulrunner.feature.feature.group 1.9.12.v20101206-2100-H28-Beta2) requires 'org.mozilla.xulrunner.cocoa.macosx [1.9.1.2a]' but it could not be found
Cannot satisfy dependency:
From: JBoss Tools RichFaces 3.2.0.v20101206-2100-H28-Beta2 (org.jboss.tools.richfaces.feature.feature.group 3.2.0.v20101206-2100-H28-Beta2)
To: org.jboss.tools.xulrunner.feature.feature.group 0.0.0