white screen of death after upgrade php version to 5.4

i have urgent problem and i need your help to fix this.
i am using wordpress multisite and domain mapping plugin for all my subdomains.
all working great with the last version of wordpress and the domain mapping plugin.
until now i worked with php 5.3, now i need to upgrade my php version to 5.4 and up...
when i change to php5.4 domain mapping start working strange and create many bugs.
most of my sites is maaped like: http://www.domain.com
so if the user will enter domain.com it redirect him to http://www.domain.com
thats work great with php5.3 if i set to php 5.4 and then i try to enter
domain.com i get white screen of death.