에러좀 .. 봐주세요..

다음과 같이 고치셔도 됩니다.

int main() {
    int **arrayCompany;
    int **arrayGrade;
    int **arrayMaxscore;
    int i;
   
    arrayCompany = (int **)malloc(sizeof(int *) * 5);
    arrayGrade = (int **)malloc(sizeof(int *) * 5);
    arrayMaxscore = (int **)malloc(sizeof(int *) * 5);
    for(i=0; i<5; i++) {
        (arrayCompany[i]) = (int *)malloc(sizeof(int));
        (arrayGrade[i]) = (int *)malloc(sizeof(int));
        (arrayMaxscore[i]) = (int *)malloc(sizeof(int));
    }

    for(i=0; i<5; i++) {
        free(arrayCompany[i]);
        free(arrayGrade[i]);
        free(arrayMaxscore[i]);
    }
    free(arrayCompany);
    free(arrayGrade);
    free(arrayMaxscore);
}