Ubuntu :: Memory Mapping Failed. Error: 1?

So, I was working with Ubuntu 9.10 and I wrote a C program which was working just fine. Then, I have installed Ubuntu 10.10 and tried to run this same program again. However, I get the following error: Code: Memory Mapping failed. Error: 1 Part of the code has the following: Code: volatile ulong *memory;

int fd = open("/dev/mem", O_RDWR | O_SYNC);
if (fd < 0) {
printf("Could not open memory.
");
return(0);
}
code....

Does anyone have an idea what the problem could be? I do not know if there would be any significant change between Ubuntu 9.10 and 10.10 that could be generating me this problem.