Nicholas,
I contacted my provider, I'll give you an update:
Our company has two websites (www.verka.nl and www.e-lay.nl). The last website is the one with this problem, the first one (www.verka.nl) is not a joomla website.
We had two different hosts by the same provider, but it was cheaper to make (for administration only) one host, so the username and password of www.e-lay.nl do not work anymore. Now I have to log in by verka.nl, that's no problem.
When I logged in by FTP (host www.verka.nl)I see the website of Verka.nl in the directory \www (root).
But in that directory I see a new one, called www.e-lay.nl. That is the joomla website.
So I had to change the host, username, password and path to backup by remote backup. So far so good. I tested the backup output directory (I made an output directory called jpbackup).
I hoped that everything worked well, but I get the same message.
When I tried to make a backup in the administration of Joomla (with the JP component) there is a message that the temporary directory is not writable.
I used eXtplorer to change the directory tmp, jpbackup, xmlrpc to full rights (777), but I have still the same problem.
Can you tell me wich directory is the used tempory directory? Maybe That will be the solution, or do you have any other idea?
Thanks for you reply,
Marco.
btw: sorry for some English mistakes, but I'm Dutch..;)