The requested Performance Counter is not a custom counter, it has to be initialized as ReadOnly

This is due to the performance counter (or category) not existing,
but with a horrible error message.

Take a look in perfmon for the counter, it should be missing on the relevant machines.

I find this happens to the .Net perf counters sometimes (no idea why) but using lodctr¹ gets them back. If you indicate which perf counter you are trying to get at we might be able to give you more help.

1. Note that the example lined is for .Net 1.1, adjust for different frameworks accordingly.