Hi Delphine,

Apologies for the late response... hopefully you have this resolved already?  If not please can you log a case via the solution finder... so just keep going with the options as nothing worked.  Go to the Knowledgebase;

http://kb.sdl.com

Then go to the tab called Solution Finder and now go here;

Download & Installation Problems

- I use SDL Trados Studio and/or SDL MultiTerm 2009, 2011 or 2014

-- I receive an error message during installation

--- I have disabled UAC during installation / I do not have Win Vista 7/8

---- None of the error messages match my issue / I tried the suggested resolution....

So if you have tried everything suggested, when you get to this point you'll be presented with a form to contact support.  Complete all the fields in the form making sure your email address is entered correctly or nobody will be able to get back in touch with you.

Also use the Chrome browser to log the case if you have it; you'll get more success in completing the form.

I hope this helps.