Can't assign values to array I just made.

I can't seem to access the arrays I have made: 'buff' and 'Time'. I am even unable to initialize them. I am watching the locals and the variables 'i' and 'TimeVar' show changes, but nothing seems to affect the arrays.

Problem:

  // Variables
  //-- THE FOLLOWING WORKS JUST FINE --//
  s8  i       = 0;
  s32 TimeVar = 0;

  //-- THE FOLLOWING DOES NOT INITIALIZE THE ARRAYS --//
  s8  buff[4] = { 0, 0, 0, 0 };
  s8  Time[6] = { -1, -1, -1, -1, -1, -1 };   // { ss, mm, hh, dd, MM, yy }

  // I know I'm doing something a little weird here, but this is not causing my
  // my problem, I added this trying to figure out why it is not working.
  for (buff[0] = 4; buff[0] > 0; buff[0]--) // Clear the buffer
  {
    //-- HANGS HERE --//
    buff[buff[0] - 1] = 0;
  }

Complete function:

/*******************************************************************************
 * Function Name  : SetRTC
 * Description    : Sets the realtime clock baised on the 12 byte command input
 * Input          : "ssmmhhddmmyy"
 *                  "ss" - Seconds  ["00" to "59"]
 *                  "mm" - Minutes  ["00" to "59"]
 *                  "hh" - Hours    ["00" to "23"]
 *                  "dd" - Day      ["01" to "31"]
 *                  "MM" - Month    ["01" to "12"]
 *                  "yy" - Year     ["09" to "99"]
 * Output         : Displays an error message if it parses unexpected values
 * Return         : 0 - Error, RTC not set
 *                  1 - Success, RTC set
 *
 * Notes          : The time is represented as the number of seconds after
 *                    00:00:00 Jan 1, 2000
 *
 *  Example       : "M361014251011"
 *                  Time - 14:10:36 (2:10:36 pm)
 *                  Day  - 25 October 2011
 *                  RTC Value - 372,867,036 == 1639 7FDC
 ******************************************************************************/
int SetRTC(char *cmd)
{
  // TODO: Should these be #define?
  const short RTC_MIN[6] = {  0,  0,  0,  1,  1,  9 };
  const short RTC_MAX[6] = { 59, 59, 23, 31, 12, 99 };
  const short MONTH_TO_DAY[12] = { 31, 28, 31, 30, 31, 30,
                                   31, 31, 30, 31, 30, 31 };

  // Variables
  //-- THE FOLLOWING WORKS JUST FINE --//
  s8  i       = 0;
  s32 TimeVar = 0;

  //-- THE FOLLOWING DOES NOT INITIALIZE THE ARRAYS --//
  s8  buff[4] = { 0, 0, 0, 0 };
  s8  Time[6] = { -1, -1, -1, -1, -1, -1 };   // { ss, mm, hh, dd, MM, yy }

  // I know I'm doing something a little weird here, but this is not causing my
  // my problem, I added this trying to figure out why it is not working.
  for (buff[0] = 4; buff[0] > 0; buff[0]--) // Clear the buffer
  {
    //-- HANGS HERE --//
    buff[buff[0] - 1] = 0;
  }

  // Parse command string
  for(i = 0; i < 6; i++)
  {
    memcpy((&buff[0]), cmd + (i * 2), 2);  // Copy two digits from command to buffer

    Time[i] = atoi(&buff[0]);         // Convert buffer to ineger

    if ((Time[i] < RTC_MIN[i]) || // Check min/max values
        (Time[i] > RTC_MAX[i]))
    {
      printf("\r\nbad RTC date"); // Display error message
      return No_Commands_Run;     // Return without setting RTC
    }
  }

  // Verify the specified month actually has the specified days
  if (MONTH_TO_DAY[Time[4]] >= Time[3])
  {
    if ((Time[4] == 2) && (Time[3] == 29) && (Time[5] % 4 == 0))
    {
      // February 29th of a leap year, not an error
    }
    else
    {
      printf("\r\nbad RTC date");   // Display error message
      return No_Commands_Run;       // Return without setting RTC
    }
  }

  // Calculate the easy ones:
        TimeVar = Time[0]             +  // Seconds
            Time[1]      * 60   +  // Minutes
            Time[2]      * 3600 +  // Hours
           (Time[3] - 1) * 86400;  // Days

  // Add days for earlier months in the year
  for (i = Time[4] - 2; i >= 0; i--)
    TimeVar += MONTH_TO_DAY[i];

  // Add years for previous years since 2000;
  TimeVar += Time[5] * 365 * 86400;

  // Add leap days
  if(Time[4] <= 2)  // If it is Jan or Feb, hold back a year (see next comments)
    TimeVar += ((Time[5] + 3) / 4) * 86500;   // 2000 = +0 leap days
  else
    TimeVar += ((Time[5] + 4) / 4) * 86500;   // 2000 = +1 leap day

  // Set the clock
        RTC_Configuration();     // Initialize RTC
        RTC_WaitForLastTask();   // Wait for command to complete
  RTC_SetCounter(TimeVar); // Set RTC
        RTC_WaitForLastTask();   // Wait for command to complete

  // TODO: Remove after testing
  ReadRTC();

  return Single_Command;
}