Hmm ... we just tried it on one of our test servers and it looks good. Is your server behind a firewall that might be preventing the access to the PPA?
~$ sudo add-apt-repository ppa:libreoffice/libreoffice-4-4
LibreOffice 4.4.x series stable backports ppa (and SRU-testing for vivid)
This ppa will:
- not contain alpha and beta releases like 4.4.0~beta2
- not contain updates to the next major (5.0.x)
- contain minor release updates and their release candidates -- these can be
considered stable
Note that for minor release updates (4.4.1, 4.4.2, 4.4.3 ...) an rc2 is almost always exactly the same as the final version.
Press [ENTER] to continue or ctrl-c to cancel adding it
gpg: keyring `/tmp/tmptovwzoom/secring.gpg' created
gpg: keyring `/tmp/tmptovwzoom/pubring.gpg' created
gpg: /tmp/tmptovwzoom/trustdb.gpg: trustdb created
gpg: key 1378B444: public key "Launchpad PPA for LibreOffice Packaging" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg: imported: 1 (RSA: 1)
OK