Tor Installation fails on Mac

[Beirne Konarski]

It has been a while since I have run Tor and wanted to get current and  
configure a server.  I pulled down the installations bundles, both  
2.0.35-0.1.14-universal and 2.1.16-rc-0.1.14-universal.  I'm trying to  
do the installation on my Intel Mac running OX X 10.5.7 and Firefox  
3.5.  When I run the installation bundle it gets partway through and  
then I get the failure message: "Install Failed.  The following  
install step failed: run postflight script for Tor."  If I look at the  
console I see this:

6/30/09 4:05:20 PM runner[44595] postflight[44638]: /Applications/ 
Firefox.app/Contents/MacOS/firefox-bin: /Applications/Firefox.app/ 
Contents/MacOS/firefox-bin: cannot execute [Exec format error]
6/30/09 4:05:20 PM runner[44595] postflight[44638]:
6/30/09 4:05:20 PM Installer[44592] Install failed: The following  
install step failed: run postflight script for Tor. Contact the  
software manufacturer for assistance.
6/30/09 4:05:20 PM Installer[44592] IFDInstallController 8619D0 state  
= 7
6/30/09 4:05:20 PM Installer[44592] Displaying 'Install Failed' UI.
6/30/09 4:05:20 PM Installer[44592] 'Install Failed' UI displayed message:'The 
  following install step failed: run postflight script for Tor.  
Contact the software manufacturer for assistance.'.

I can run firefox-bin from the command line copying and pasting the  
path.  I made sure Firefox wasn't already running.  I also tried a  
custom install with the Torbutton turned off but still got the error.   
Any ideas?