Sorted:

object has no hasOwnProperty method (i.e. it's undefined) – IE8-Collection of common programming errors

Undefined method `level` for Mongoid logger in a Rails app-Collection of common programming errors

problem about entity-attribute-value-Collection of common programming errors

problem about tooltips-Collection of common programming errors

C# XNA Xbox, in this case optional parameters are not optional-Collection of common programming errors

Google closure: trouble type checking parameters that should be functions-Collection of common programming errors

Automatic HEq instances for members of an HList-Collection of common programming errors

Generate the list of Ints associated with an Enum type-Collection of common programming errors

Where should I get my tattoo?-Collection of common programming errors

Chrome: doesn't print javascript content-Collection of common programming errors