this may help depending..
I just upgrading from an older version of php to 4.2.0 and had soooo much trouble with all my scripts, especially what seemed to be the apparent random amount of blank screens.
anyhoo, because I had worked on older versions of php with global variables turned on by default, passing variables was no problems. But with 4.2.0 it is turned off by default thus not allowing basic variables to passed anywhere, hence if you are sending a variable to another page from a form and just call it using $whatever, it won't work hence blank screen.
Either turn on global variables in php.ini or use $HHTP_POST_VARS['whatever'] to access posted variables.
hope this helps as I have spent last two weeks pulling my hair out until I realised this simple but critical issue.
bonneyskinner@hotmail.com