PerformanceCounter.NextValue hangs on some machines.

Question

I don't know why, but many computers hangs on following operation:

void Init()
{
    net1 = new List<PerformanceCounter>();
    net2 = new List<PerformanceCounter>();
    foreach (string instance in new PerformanceCounterCategory("Network Interface").GetInstanceNames())
    {
        net1.Add(new PerformanceCounter("Network Interface", "Bytes Received/sec", instance));
        net2.Add(new PerformanceCounter("Network Interface", "Bytes Sent/sec", instance));
    }
}

//Once in 1 second
void UpdateStats()
{
    Status.Text = "";
    for (int i = 0; i < net1.Count; i++)                    
         Status.Text += string.Format("{0}/{1} Kb/sec;   ", net1[i].NextValue() / 1024, net2[i].NextValue() / 1024);
}

On some computes program hangs completely on first call of UpdateStats(), others experiencing 100% CPU load but program works (slowly). Other counters like new PerformanceCounter("Processor", "% Processor Time", "_Total") seems to work fine.

Any suggwstions why is that?