conversion to mp4 format fails

hello everyone in the adobe presenter community!

First of all, i would to apologize my bad english, as it's not my native language. (i'm french, so feel free to answer me in my own language if you can !)

I'm facing a problem with presenter 11 and i don't find anything in that forum nor in the user-guide.

in fact it doesn't react the same way presenter 8 did.

i'm working in office 2013 and since the upgrade to presenter 11, when i want to preview any job or presentation, a problem happens during conversion process (conversion of media1.wmv to mp4...) the process fails, and the software "adobe converter" shows up and nothing else happens !

before, everything was automatic, adobe converter never poped-up like that !!, and i don't know how to get rid of this annoying problem !

if only "converter" was doing his job... but nothing is running at all !

i just quit the software and this acion cancel the entire process

it happens also when i want to generate the presentation (not only in preview mode)

please tell me what am i doing wrong ? i'm probably missing something stupid, but i need to get my jobs done !

any ideas are welcome !

kind regads