There are two reasons I can think of why either Sensor wont work.
#1 Order of Scripts
If you have another script below either Sensor script that overwrites Event Update method, neither Sensor will trigger a Page Change.
#2 Event Page Configuration
Each Event can have multiple Pages, but on each of those Pages, the Conditions need to be different. IE, on Page 1, there are No Conditions, but on Page 2, Self Switch D should be checked as a Page Condition. Thats the simplest form of a Sensor with both scripts. As an experiment, try putting in different Graphics on each page. That way you can at least tell that the Event Page changes, then you can move on to Triggers not working.