Make Wamp create backup of wampmanager.ini during first startup - name it wampmanager.ini.bak
it will help a lot people (like me) who got this file broken (empty).
Happen to me 3rd time this week, need to reinstall wamp third time cause there's no copy fo this file and no way to restore it alternatively.
If you loose your wampmanager.ini file but you still have the wampmanager.tpl file all you need to do is run a refresh from the wampmanager icon in the system tray and it will be regenerated.
i.e.
right click wampmanager -> refresh