"Missing a temporary folder" the on going dreaded topic

So, due to my struggles on getting my website up and running; i’m finally there! There’s just one tiny bit that’s bottering me.

When i try to install a different theme or insert media, i get a error messade that it couldn’t be uploaded due to “Missing a temporary folder”.

I’ve done this:

* I have tried to locate where wp will use the temp by adding the php-note and search the browser for the route = no luck
* Watched all tutorials on youtube about this = no luck
* reading every possible thread about this on multiple forums = no luck
* Tried to create my own /tmp or /temp in the root = no luck
* Tried to config the documents using ftp programs = no luck
* Trying to contact my webhost (web10) several times but no answer = no luck

I don’t know what to do now. I feel like a complete idiot for not solving this yet. Any suggestions?