>Does the PATH in that link refer to the length of the path for a particular file name, or to the length of a SET PATH ?

I think it refers to the PATH environmental variable. It will be nice if Sergey can clarify - or you can check the link he provided as a reference to be sure.
>
>>>>>>Having a nonexistent directory in the path can make a system really sloooooow.
>>>>>
>>>>>
>>>>>Ooops !
>>>>>That's true, specially with Vista and Seven.
>>>>>Does that fit to your case Jon ?
>>>>
>>>>If you "trip over" the 254 character per line limit and the last directory name is cut off, you will also end up with a nonexistent directory name.
>>>
>>>My path is 382 bytes long. What limit?
>>
>>Take a look here
>>
>>Windows Limitations of Path