is array size limited?

Hi,

When i run the program below with the array size as 255,the random values are getting stored in the value array correctly.But if I increase the size of the array to 256 only '0's'(zeros) are getting stored at all the locations?How can I overcome this error?
is there any limitation for the size of the array in keil?

looking for ur help,
t.senthil

	#include <stdio.h>
	#include <stdlib.h>
   #include <LPC22xx.h>

	void main (void)
	  {



	 unsigned int values [255],i;
	  for (i=0;i<255;i++)
	  values[i]=rand()%100;

	  }