Programming :: C Code Fails On Repeatedly Opening /proc?

I am trying to run my code repeatedly in a loop about 50 times for timing measurement. I have C code running on ubuntu 8 on a single processor, Intel x86. My code is something like this

Code:
for (loop =0;loop<=50;loop++)
{
// other operations
pDir = opendir("/proc");
while (pDir == NULL)

[Code]...

After about 28-29 times the loop stops executing. I initially had a return -1 if I got pDir == NULL. That caused my program to exit, and I dont want that. Any clues on why this happens, and how I can circumvent this?