Two years later, I remembered to auto answer me and mark this as solved, so, copy paste from my own edit:
Solved:
Finally found the problems...
a) The project had declared two structs (struct petecander and struct structPetecander), and the compiler was telling me about "struct structPetecander" not having an element of structPetecander. Of course it didn't have it as it was another struct with a damn similar name.
b) I was getting a "too many arguments for function_that_I_added_the_argument". Too many time programming in Java made me forgot that in C you have to declare in a .h the function
Two error messages (buried below the other errors) gave me the hint. Sorry for the bad translation: /module.c:: error: conflict type for /headers.h:: error previous declaration of was here
Time to go to cry a bit to a corner, I guess.