I’ve got encountered problem when try to add new repository to ubuntu 12.04 using apt :

Traceback (most recent call last):
    File "/usr/bin/apt-add-repository", line 125, in <module>
    ppa_info = get_ppa_info_from_lp(user, ppa_name)
File "/usr/lib/python2.7/dist-packages/softwareproperties/ppa.py", line 84, in get_ppa_info_from_lp
    curl.perform()
pycurl.error: (60, 'server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none')

this error happen since ppa.py depend on pycurl, curl trying to verify peer and host with curl.setopt(pycurl.SSL_VERIFYPEER, 1) and curl.setopt(pycurl.SSL_VERIFYHOST, 2):

def get_ppa_info_from_lp(owner_name, ppa_name):
lp_url = LAUNCHPAD_PPA_API % (owner_name, ppa_name)
    # we ask for a JSON structure from lp_page, we could use
    # simplejson, but the format is simple enough for the regexp
    callback = CurlCallback()
    curl = pycurl.Curl()

    curl.setopt(pycurl.SSL_VERIFYPEER, 1)
    curl.setopt(pycurl.SSL_VERIFYHOST, 2)

    curl.setopt(pycurl.WRITEFUNCTION, callback.body_callback)
    # only useful for testing
    if LAUNCHPAD_PPA_CERT:
        curl.setopt(pycurl.CAINFO, LAUNCHPAD_PPA_CERT)
    curl.setopt(pycurl.URL, str(lp_url))
    curl.setopt(pycurl.HTTPHEADER, ["Accept: application/json"])
    curl.perform()
    curl.close()
    lp_page = callback.contents
    return json.loads(lp_page) 

from http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTSSLVERIFYHOST you can bypass this verification using pass a long set to 0 :

...
curl.setopt(pycurl.SSL_VERIFYPEER, 0)
curl.setopt(pycurl.SSL_VERIFYHOST, 0)
...