Eclipse Make failing


I have been building a project in eclipse, it was working fine for quite a
while and then all of a sudden I got this error:

No rule to make target ‘all’

when I try to build

No rule to clean target ‘all’

when I try to clean

My brother thinks that something has gone wrong in the hierarchy of my
project. I have no clue how to fix this.

Any help would be greatly appreciated