When used in a reference pointcut the bean() PCD doesn't work. AspectJ (specifically, PatternParser.parseReferencePointcut() called by parseSinglePointcut()) treats bean() is a similar way to this(), target(), @target() etc. and tries to validate the argument to bean() as a type. Obviously, it can't find a matching type and ends up throwing an exception.
The test code for the bug is in BeanNamePointcutAtAspectTests (currently commented out).