There is a relationship between poverty and child labour, but this has very little to do with any economic compulsion that poverty normally implies. It is a much more generic issue.
Child labour and illiteracy is yet another example of the poor not being heard because they are not important enough. It arises out an inability on the part of the poor to access the right quarters and to articulate their demand effectively and has little to do with lack of income or affordability. It is an entitlement that the poor have been denied.