HELP ME WITH THIS ERROR IN MY COMPOSITION

They should - that fact they are not suggests to me three possibilities:

1. The "daughter"comps you see in the project panel are not the "daughters" in the "mother" comp.  What happens if you double-click on a daughter comp and make changes there?
2. Your graphics card has crashed and changes you're making are not updating.  Restarting should resolve this.
3. This is a template project you've downloaded and the creator is using obscured expressions to control the daughter content.

If you can post screenshots of the following, I think it would help:

• Your entire comp window, showing the mother comp's timeline
• One of the daughter comps before and after changes with the timelines too and any properties you've changed expanded on the timeline
• The project panel with all folders expanded (if it's from a template)

You need to provide much more info about the actual contents of the comps, screenshots, info about your computer and so on.

Mylenium

Moved to After Effects space.