ok,
the [output~] that you see in the help patches is not actually an 'object' but rather it is an 'abstraction'. the difference is that an object is made of C code, where an abstraction is just a pd patch made of other pd objects. actually, any pd patch that you make can be used as an abstraction inside of other pd patches. if your pd patch is called 'crazyfilter.pd' then you would just type 'crazyfilter' into an object box, and then that patch can be used as an abstraction.
now, the reason why the [output] abstraction is not working for you, is that pd is not set to scan your entire hard drive everytime you use an abstraction. at startup, pd loads a group of directory paths that are searched when new objects are made. if you click on 'file' in the menu bar, you will see that there is a section for 'path'. the directories contained in there will be searched every time pd needs to find an object/file/etc.
so, if you create a new file, and try to create [output~], it won't load, because the path to the directory containing the output~.pd abstraction is not set. here you have a couple of options. the obvious one is to set .../doc.3/audio examples/ as a path.
however, i think a better option is to create a folder of your own called 'my-abstractions' or something like that. and set the path to that directory in the file->path menu. then, open the output~ abstraction, click 'save as' and save a copy into your my-abstractions folder.
that way you can use [output~] in any patch.
one more thing. as well as searching the directories listed in file->path, pd will also search the directory containing the currently opened patch. that is the reason why you can create [output~] in any of the doc.3/audio examples/ patches without specifically telling pd to search that path.