Comment 5 for bug 1310552

Related:
https://bugs.php.net/bug.php?id=67075
http://askubuntu.com/questions/451953/php-pear-is-not-working-after-upgrading-to-ubuntu-14-04

This doesn't helps (actually the mentioned patch seems to be already applied to the Ubuntu files):
http://cweiske.de/tagebuch/pear-php-5.5.htm

This workaround seems to work for me (still playing around with it). It probably also works for "pear install".
========
# First run pear to download the packages. It will probably put the packages into
# /build/buildd/php5-5.5.9+dfsg/pear-build-download/
# but it can't install them.
$ pear upgrade

# Un-Gzip the downloaded packages.
$ gunzip /build/buildd/php5-5.5.9+dfsg/pear-build-download/*.tar

# Now pear should be able to work with the pure tar-files.
$ pear upgrade /build/buildd/php5-5.5.9+dfsg/pear-build-download/*.tar
========

So by this workaround I guess, the bug's reason is something about the gzip compression.