I'm trying to add multiple PHP version in Plesk 12. Switching my domain to the new version PHP 5.4.29 result in this error:

(104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server

Here is phpinfo() of the complied PHP version, obtained running php54-cgi index.php from the terminal. The same script placed under document root doesn't work in FastCGI.

How can I debug/try to figure out what's the error?

Currently running CentOS 6.5 x64, Plesk v12.0.18_build1200140529.2, PHP 5.5.13. I've downloaded PHP 5.4.29:

cd /usr/local/src
curl -O http://it1.php.net/distributions/php-5.4.29.tar.gz
cd php-5.4.29

And configured with:

./configure \
--prefix=/usr/local/php54 \
--with-bz2 \
--with-config-file-path=/usr/local/php54/etc \
--with-config-file-scan-dir=/usr/local/php54/etc/php.d \
--with-curl \
--with-gd \
--with-gettext \
--with-iconv \
--with-layout=PHP \
--with-libxml-dir=/usr/local/php54 \
--with-mhash \
--with-mysql=mysqlnd \
--with-mysqli=mysqlnd \
--with-openssl \
--with-pdo-mysql=mysqlnd \
--with-readline \
--with-xsl \
--with-zlib \
--enable-calendar \
--enable-cgi \
--enable-exif \
--enable-ftp \
--enable-intl \
--enable-mbstring \
--enable-pcntl \
--enable-shmop \
--enable-sockets \
--enable-sockets \
--enable-sysvmsg \
--enable-sysvsem \
--enable-sysvshm \
--enable-wddx \
--enable-zip

Then:

make && make install
Installing PHP CLI binary:        /usr/local/php54/bin/
Installing PHP CLI man page:      /usr/local/php54/php/man/man1/
Installing PHP CGI binary:        /usr/local/php54/bin/
Installing PHP CGI man page:      /usr/local/php54/php/man/man1/
Installing build environment:     /usr/local/php54/lib/php/build/
Installing header files:          /usr/local/php54/include/php/
Installing helper programs:       /usr/local/php54/bin/
  program: phpize
  program: php-config
Installing man pages:             /usr/local/php54/php/man/man1/
  page: phpize.1
  page: php-config.1
Installing PEAR environment:      /usr/local/php54/lib/php/
[PEAR] Archive_Tar    - installed: 1.3.11
[PEAR] Console_Getopt - installed: 1.3.1
warning: pear/PEAR requires package "pear/Structures_Graph" (recommended version 1.0.4)
warning: pear/PEAR requires package "pear/XML_Util" (recommended version 1.2.1)
[PEAR] PEAR           - installed: 1.9.4
Wrote PEAR system config file at: /usr/local/php54/etc/pear.conf
You may want to add: /usr/local/php54/lib/php to your php.ini include_path
[PEAR] Structures_Graph- installed: 1.0.4
[PEAR] XML_Util       - installed: 1.2.1
/usr/local/src/php-5.4.29/build/shtool install -c ext/phar/phar.phar /usr/local/php54/bin
ln -s -f /usr/local/php54/bin/phar.phar /usr/local/php54/bin/phar
Installing PDO headers:          /usr/local/php54/include/php/ext/pdo/

Copied php.ini-production to /usr/local/php54/etc/php.ini and added a new handler in Plesk:

/usr/local/psa/bin/php_handler --add -displayname 5.4.29 -path /usr/local/php54/bin/php-cgi -phpini /usr/local/php54/etc/php.ini -type fastcgi -id php54

Symbolic linking:

ln -s /usr/local/php54/bin/php /usr/local/bin/php54
ln -s /usr/local/php54/bin/php-cgi /usr/local/bin/php54-cgi

New installed version:

php54-cgi -m

[PHP Modules]
bz2
calendar
cgi-fcgi
Core
ctype
curl
date
dom
ereg
exif
fileinfo
filter
ftp
gd
gettext
hash
iconv
intl
json
libxml
mbstring
mhash
mysql
mysqli
mysqlnd
openssl
pcntl
pcre
PDO
pdo_mysql
pdo_sqlite
Phar
posix
readline
Reflection
session
shmop
SimpleXML
sockets
SPL
sqlite3
standard
sysvmsg
sysvsem
sysvshm
tokenizer
wddx
xml
xmlreader
xmlwriter
xsl
zip
zlib

[Zend Modules]