Galaxy imported a library which already existed in the python system
folder. See the error message below.

Is that because RedHat 6 used a "python-marksafe", but Galaxy installation program did not recognize it? Or Galaxy require a higher version of markupsafe module?

/home/xxxxx/work/galaxy-dist/
lib/galaxy/__init__.py:79: UserWarning: Module
markupsafe was already imported from
/usr/lib64/python2.6/site-packages/markupsafe/__init__.pyc, but
/home/xxxxx/work/galaxy-dist/eggs/MarkupSafe-0.12-py2.6-linux-x86_64-ucs4.egg
is being added to sys.path
  self.check_version_conflict()

The system package is python-markupsafe-0.9.2-4.el6.x86_64
Galaxy has a newer version, it is
MarkupSafe-0.12-py2.6-linux-x86_64-ucs4.egg

Any idea how to resolve this problem?