c - EXC_BAD_ACCESS error message in Xcode -

i'm writing project in xcode, , can't seem solve error. i'm aware i'm trying access released/un-initialised object somewhere, or perhaps passing data objet doesn't understand, can't find cause of issue (i.e. line doing this). i've tried debugging using nszombies, , didn't work.

int main(int argc, const char * argv[1]) { const int   time_quantum = atoi(argv[2]);  int         totaltime = 0;       int         blockedtime = 0;     int         blocktime[100];      int         exittime[100];      int         reltime[100];        int         spawntime[100];    int         processid[100];     char        state[100][32];       int         microseconds = totaltime * 1000; int         currentsector = ((int)((microseconds/1000000.0) * sectors_per_sec)) % disk_sectors;  int runningtest;  file *fp; fp = fopen(argv[1], "r");   char row[bufsiz];  while (fgets (row, sizeof(row), fp) != null) //error returned here {     int time;     char eventtype[32];     int pid;     int sector;      sscanf(row, "%i %s %i %i ", &time, eventtype, &pid, &sector); 

there more code follows, it's excruciatingly long-winded , convoluted, , don't think has relevance error. initial hunch problem has "fp" call; might have botched file opening , trying call on non-existent object. tried:

    while (fscanf(fp, "%d" "%s" "%d" "%d", &time, state, &pid, &sector)!= eof){  

but, replaced what's there after time. know bad access is? have no clue. file i'm supposed opening sample process schedule file, containing info processes (when spawn, exit , blocked etc.). if nudge me in right direction, appreciate it.