The code seems to be ok.
By the way it would be more polite to call addUsrNav after begin method.
I cannot test the code as i would need to set up the same custom analog buttons.
You can try the following on my behalf
Replace the actual method addUsrNav in MENWIZ.cpp with the following
void menwiz::addUsrNav(int (*f)()){
ERROR(0);
btx=(_nav*)malloc(sizeof(_nav));if(btx==NULL){ERROR(900); return;}
usrNav.fl=true;
usrNav.fi=f;
}
Let me know