Hi, with question number 1.
Can you ping the repo in question? Can you get outside your network? Can you view the repos in some utility, browser etc? If so I have found that any sort of updating can fail due to, bad DNS, improper time configuration, bad HOSTNAME setup, etc.
Question 2 I am sorry to say I can't help you with but I am sure the search utility can help you.
but i don`t know if my config file is wrong or the proxy doesn`t give me enough privilegies
Is this a home setup or elsewhere?