[horde] horde installation fails (using pear)

[lameventanas at gmail.com]

Attempting to install horde by using pear as recommended and described
in the manual, I run this:

pear install -a -B horde/horde

and I get these errors:

Package "pear.horde.org/horde" dependency "pear.php.net/Net_DNS2" has no
releases
Package "pear.horde.org/horde" dependency
"pear.php.net/Services_Weather" has no releases
Package "pear.horde.org/horde" dependency "pear.php.net/Console_Getopt"
has no releases
Package "pear.horde.org/horde" dependency "pear.php.net/Console_Table"
has no releases
Package "pear.horde.org/horde" dependency "pear.php.net/File_Find" has
no releases
Package "pear.horde.org/horde" dependency "pear.php.net/File_Fstab" has
no releases
Package "pear.horde.org/Horde_Core" dependency "pear.php.net/PEAR" has
no releases
Failed to download horde/Horde_Backup within preferred state "stable",
latest release is version 1.0.0RC1, stability "beta", use
"channel://pear.horde.org/Horde_Backup-1.0.0RC1" to install
Package "pear.horde.org/Horde_Core" dependency "pear.php.net/Net_DNS2"
has no releases
Package "pear.horde.org/Horde_Core" dependency
"pear.php.net/Text_CAPTCHA" has no releases
Package "pear.horde.org/Horde_Core" dependency
"pear.php.net/Text_Figlet" has no releases
Package "pear.horde.org/Horde_Core" dependency
"pear.php.net/Text_LanguageDetect" has no releases
Package "pear.horde.org/Horde_Mapi" dependency
"pear.php.net/Math_BigInteger" has no releases
horde/horde can optionally use package "pear/Net_DNS2"
horde/horde can optionally use package "pear/Services_Weather"
horde/horde can optionally use package "pear/Console_Getopt"
horde/horde can optionally use package "pear/Console_Table"
horde/horde can optionally use package "pear/File_Find"
horde/horde can optionally use package "pear/File_Fstab"
horde/Horde_Core requires package "pear/PEAR"
horde/Horde_Core can optionally use package "horde/Horde_Backup"
(version >= 1.0.0, version <= 2.0.0alpha1, excluded versions: 2.0.0alpha1)
horde/Horde_Core can optionally use package "pear/Net_DNS2" (version >=
1.3.0, version <= 2.0.0alpha1, excluded versions: 2.0.0alpha1)
horde/Horde_Core can optionally use package "pear/Text_CAPTCHA"
horde/Horde_Core can optionally use package "pear/Text_Figlet"
horde/Horde_Core can optionally use package "pear/Text_LanguageDetect"
horde/horde requires package "horde/Horde_Core" (version >= 2.30.0,
version <= 3.0.0alpha1, excluded versions: 3.0.0alpha1)
horde/Horde_Form requires package "horde/Horde_Core" (version >= 2.0.0,
version <= 3.0.0alpha1, excluded versions: 3.0.0alpha1)
horde/Horde_Rpc requires package "horde/Horde_Core" (version >= 2.5.0,
version <= 3.0.0alpha1, excluded versions: 3.0.0alpha1)
horde/Horde_Rpc can optionally use PHP extension "soap"
horde/Horde_Rpc can optionally use PHP extension "xmlrpc"
horde/Horde_Dav requires package "horde/Horde_Core" (version >= 2.0.0,
version <= 3.0.0alpha1, excluded versions: 3.0.0alpha1)
horde/Horde_Mapi requires package "pear/Math_BigInteger" (version >=
1.0.2, version <= 2.0.0, excluded versions: 2.0.0)
horde/Horde_ActiveSync requires package "horde/Horde_Mapi" (version >=
1.0.0, version <= 2.0.0alpha1, excluded versions: 2.0.0alpha1)
No valid packages found
install failed

Any ideas?