I just did a fresh install of 1.2.6rc2 on a server that has php 4.3.11 available. I have asked the hostingprovider to give me access to a newer version of php as I know this is less than the recommended/required version.
But in the meantime setup.php gives me a curious fatal error:
Fatal error: Call to undefined function: file_put_contents() in /home/.sites/39/site9/web/zp-core/setup.php on line 1097
Isn't this function php 5 and higher, so should not be used for php 4?
Hope this helps in some way :-)