It worked the other way round. the following line was the problem.
unsigned int iCounter[12] = {0};
After a lot of different tries, finally i got this way of initializing works fine without any warning and error. I am adding this to the answer part, so that someone else having similar problem might get help from this.
struct Node {
Node(): iCID(0), sVoting_PN("") {
for(unsigned int l=0;l<T_LITTRAL;l++){
sTS[l]="";
if(l<AMOUNT_OF_ARTISTS){
iCounter[l]=0;
}
}
}
//member variables
unsigned int iCID;
std::string sVoting_PN;
std::string sTS[T_LITTRAL];
unsigned int iCounter[AMOUNT_OF_ARTISTS];
Node *next;
};