Error: is not valid integer value in C++

I have a func:

int readCoord(String coord) {
    String pos;
    String whatFind = coord + "=";
    int startPos = PosEx(whatFind, XX);
    int endPos = PosEx(";", XX, startPos);
    pos = XX.SubString(startPos+2, endPos - startPos-2);
    int posConverted = StrToInt(pos);
    return posConverted;
    ShowMessage(pos);       // LOG
}

Used in:

int posX = readCoord("x");
Label4->Caption = posX;   
int posY = readCoord("y");
Label5->Caption = posY;    
int posR = readCoord("R");
Label6->Caption = posR;

But there is a problem:

" is not valid integer value

I do not see any errors.