When you said,
"… I just Installed 188.8.131.52 and the The Key and it works Fine…"
Are you saying that you entered the Fab 5 key with the Fab 4 application?
I doubt this would work.
I suspect you may have inadvertantly retrieved the Fab 4 key again, if in fact, you just activated Fab 4 with a key.
On Fengtao’s support page:
There’s a dropdown for key retrieval. The default key right now is
Please click on the dropdown to display:
DVDFab 5.x Beta