A Type Initializer exception indicates that the type couldn’t be created. This would occur typically right before your call to your method when you simply reference that class.
Is the code you have here the complete text of your type? I would be looking for something like an assignment to fail. I see this a lot with getting app settings and things of that nature.
static class RHelper
{
//If this line of code failed, you'd get this error
static string mySetting = Settings.MySetting;
}
You can also see this with static constructors for types.
In any case, is there any more to this class?