Thank's Mark !

I confirm that I use exactly the same procedure with the ILS. And as you can se on my screenshot, the autoland does work perfectly... but without the horizontal and vertical guides.  :D

So far, the last possibility left is a corrupted file. So I will download a new 757.exe this week-end, clean the regsitries and re-install the bird... once again !  :P

About the "unusual line", I haven't been clear : it's my fault, it's just a visual effect due to the fact that I have moved the camera back, just at the pilot's seat level. It's a piece of the top of the pilot's seat that you see, nothing to see with a problem with my GC  ;)

Once again, thanks for your help.