Victor Feinman I found it on some guy's site

Sitecore – FieldRenderer.Render(item, fieldname) returning “” empty string

Today I spent 2 hours trying to debug why FieldRenderer.Render() was returning an empty string.

It was working yesterday and the code didn't change, so what was it?

WARN Could not create an instance of the counter …

Sitecore log files bigger than they should be? Are you finding "Could not create an instance of the counter" ... numerous times? Well this seems to be a common problem especially if you have manually installed Sitecore. The problem is that the counters are not installed. Sitecore has realized this and created a script to install the necessary performance counters.