I did not get it work. I decided to write my own bot. When i finished the Server gave me a "nonce to small error" which can be interpreted as "your privat key and secret key are already in use". Which was not done by my own program and the key was only used for the php bot. I deleted the old keys, created a new one and everything worked as it should.
Any idea how or why that happened ?
nonce to small means you aren't passing a good nonce id to your API key. It needs to be a unique always incrementing number passed with every query. I use the microtime in Marginbot.