This is a javascript error/bug, usually caused by using custom html widgets, google adsense code is a  known cause also

Thanks for your answer.
I don't have an adsense plugin. I go for search.

google adsense code is javascript as well meaning its not google adsense its javascript I have tested this bug with several codes other than adsense if you can tell us the url it would be easier to see if we can locate the issue

For exemple when I want to edit this page http://www.camikas.fr/photo/view/11

could be your google anylatic code that you have in your footer (which by the way is showing twice)

apparently not, i desactivate et delete the twice code.
But still the same problem.
I ve seen a mp3 html code at the footer, don't know where it comes from:
<audio id="ajaxim_sound_player_audio" src="http://www.camikas.fr/ow_static/plugins/ajaxim/sound/receive.mp3" />

thats from ajax IM, either way its a javascript error, try viewing your site in firefox

I use FF as navigator and I can't read javascript.
Ajax IM doesn't appear in my plggin administration files

sorry i meant firebug

it's the floatbox_container block

Do you see any errors on your site when using Firebug? It definitely looks like there is a JS error.

i got this error in console :
Le « Content-Type » HTTP « audio/mpeg » n'est pas géré. Le chargement de la ressource média http://www.camikas.fr/...im/sound/receive.mp3 a échoué. https://apis.google.com/...TiA/cb=gapi.loaded_0 Line 150

I uploaded an image successfully yet there is an error related to the  http://ds.addthis.com/ website. Did you add any custom code related to this website?

I added this pluggin after the error appears.
I tried another firebug console error test and this appeared :
data.selectorText is undefined http://www.camikas.fr/ow_static/plugins/base/js/htmlarea.js Line 81

this the code from line 81 :
if( data.selectorText.match(/body\.htmlarea_styles/i) ){
                                    window.htmlAreaData.tempStyles += ( $.browser.msie ? data.selectorText + '{' + data.style.cssText + '}' : data.cssText );
                                }

Send me your Admin Panel and FTP access details via PM. We will check into your problem.

done

pb resolved after update, thanks for your help