Sorted:

In emacs, how can I add a function to hook when the function hasn't yet been defined?-Collection of common programming errors

Comparing design by contract to type systems-Collection of common programming errors

C's pow function refuses to work with variable exponent-Collection of common programming errors

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