Curently I am trying to install VisTrails OS X Version. I notice from the installer (can be downloaded here), the OS X version is for 10.5 (Leopard). And after trying a few times, VisTrailes apparently is not 10.6 compatible (yet). I guess Apple is changing a lot with this OS X Version but did not put anything to handle backward compatibility, especially OpenGL based program.
Fortunately, the guys from University of Utah is kind enough to help me to do the installation. Here are a few steps to get VisTrails on OS X 10.6:
1. go to terminal
2. rm -rf ~/.vistrails
and rm -rf ~/.matplotlib
This first two step is to make sure that previos vistrail error removed from your OS setting. I guess when you open VisTrails, it writes lots of (hidden) things in your OS
3. install VisTrails as usual at your Applications folder
4. in terminal type cd /Applications/VisTrails/Vistrails.app/Contents/Resources/lib/python2.5
5. type DYLD_LIBRARY_PATH=/usr/lib DYLD_PRINT_LIBRARIES=1 /System/Library/Frameworks/Python.framework/Versions/2.5/bin/python
6. it will compile something and then ask for input:
>>> import matplotlib.axis
7. It will compile few things and then type exit()
After this steps, you will be able to run VisTrails normally. Great program for Scientific Visualization.