Also try adding a statement like this: die("Got this far"); and moving it farther and farther back until you find the exact place where it no longer runs.
I managed to trace the stop to the line "require_once( 'GlobalFunctions.php' );" in Setup.php
No code in GlobalFunctions.php is executed.
In config/index.php, the "require_once( 'Setup.php' ) is around line 365.
Could it be a out-of-memory problem?