Question Upgrade from 2.0 to 3.0 Failed

Hi there. I´ve checked most of the topics and I think there is no one related to the problem I´m having.
I´ve attempted to upgrade kunema to 3.0. For that I first upgraded Joomla to 2.5.11.
After that I wen´t to the extention manager and tried to ways of upgrading kunena:
1) Download kunena 3.0 files, upload and install
2) Install using the URL provided in the guide.
In both cases I have the same problem.
Kunena Installation failed!
Sorry, installation failed with the following error:
{"success":true,"status":"33%","current":"Prepare Installation","log":"\n\t\n\t\t
Prepare Installation<\/td>\n\t\t \n\t\t... OK<\/td>\n\t\t <\/td>\n\t<\/tr>\n\t<\/table>\n"}
When I hit Details to see the exact problem it just stays there with no action but:
Installation Details
Preparing installation...
I´ve tried going into my website folder and deleting all kunena files, components, modules, plugins etc. and trying a clean install. Still no solution.
On the background I see the msg Kunena installation succesfull but when I go to kunena component it tryes to install it again and it is listed also on available updates. In both cases when I try to complete it I get the sema problem.
NOTE: I´ve tried clearing cache and trying again. Same problem.
I attach a screen of the situation.

Hi looks like a other plugin is conflicting.

Please disable all other none joomla plugins, and try again.

Thx for the reply. Disabled all Plugins and tried again. I had the same problem both with the downloaded file from the webpage and the link in the guide.

So you have still the error?
Can you provide me a link, with a admin account. Then i will check it.

For security reasons I cannot put it here but i sent it to you by private mesage by facebook. I could´t find the private msg in this forum.
Thx!

you can contact me by Skype:
jelle810