Since "YuYu Hakusho the Movie" was already taken 
by AnimeWorks when US Manga released what was to 
be the second movie here, US Manga used the 
*series* title they intended for it if they 
released more. (I'm sure, to aviod confusion of 
the two movies.) There never *was* a secondary 
title on that movie to begin with. "Poltergeist 
Report" is their translation of the series 
title: "YuYu Hakusho". (For more proof, try 
running the title through a literal translator - 
mine gives me "ghostly white pages", or somesuch. 
So you can see it's not a different title.)

They probably put "YuYu Hakusho in small print 
under the title for the same reason the Fushigi 
Yuugi tapes say both "Fushigi Yuugi" and
"Mysterious Play". So that people who were 
already fans of the series can find the thing, 
not because the series had some kind of subname.

Many Sharp Smiles,
--Drac