Two things:
The component on the inactive page that you want to change must be vscope global.
When referencing the component you need to say which page it is on (the library is a bit weak in this regard), so either declare the component with the page prefix: NexText t0 = NexText(1, 1, "page1.t0"), or go lower level and write the command manually: sendCommand("page1.t0.txt="cheese").