All I can do, on my behalf, is to describe preciacelly the procedure I follow every time I try (successfully up to now) to convert a stadium from previous FIFA edition to FIFA'14:
-Open Rinaldo's Creation Master '14
-Click on Stadiums section/icon
-Find an original generic stadium that already exists in original FIFA Game (e.g. Akaaroa Stadium, Aloha Park, Arena d'Oro etc.)
-Clone the chone original stadium
-Click on "Save"
-Unzip via WinRar the downloaded stadium patch (for instance BayArena) at the same direction I installed the stadium patch (e.g. on Desktop, in My Documents or in my external disc)
-Open the sub-files, such as:
a). Sceneassets: i.Crowdplacement, ii.Fx (glares) and iii.Stadium,
b). Ui -> artAssets -> i.Stadium and ii.Stadiumsbig (if there are included) and change the i.d.s according to my game's data base
-Open Moddingway's FIFA14 - FHL-BH-Editor and when it opens, I always click on/choose: "Regenerate All BH-Files (Take Care of Extern Files)"
-Open again Rinaldo's Creation Master '14
-Click on Stadiums section/icon
-Assign the Stadium to specific team (let's say BayArena to Bayer '04 Leverkuzen)
-In case that these files are not included (Ui -> artAssets -> i.Stadium and ii.Stadiumsbig), I create new photos via Photoshop (Overcast Day, Clear Day, Night and Sunset) and insert them in: "Preview" Stadium section. After trying and searching a lot, I found out that the photos' dimensions are: A. 1024x256 => 610x240 and B. 1024X512 => 610X272 (the reason this is that I don't know yet how to create photos in game and save them in my Photos).
-Click on "Save" and Finished.
Hope it may help you...