I am having the same exact problem. I tried changing the name of the catalog directory back to catalog (from my original choice), double checked all the chmod settings in install files and dirs, even chmoded catalog dir to 777, tried installing ZC into different dir paths nothing worked.

M Using PHP 5.1.6-15.e15, ZC 1.3.8a on a Centos 5.1 box. Any suggestions?