PHP DOMDocument missing

Я получаю странную ошибку при запуске $ dom = new DOMDocument (" 1.0 "," utf-8 ") ;: Предупреждение : require_once (classes / DOMDocument.class.php) [function.require-once]: не удалось открыть поток: нет такого файла или каталога в / var / www / html / cms / bootstrap .php в строке 5

Неустранимая ошибка : require_once () [function.require]: Не удалось открыть "классы / DOMDocument.class.php" (include_path = '.: / usr / share / pear: / usr / share / php: / var / www / html / cms / plugins / Zend / library ') в /var/www/html/cms/bootstrap.php в строке 5

Согласно php.net/manual/en/dom.setup.php, мне нужно установить php-xml. Я пробовал это, но это тоже дает ошибки ...

[user@lnxcmsdev cms]$ sudo yum install php-xml
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * addons: mirror.web-ster.com
 * base: mirror.hmc.edu
 * extras: mirror.hmc.edu
 * rpmforge: ftp-stud.fht-esslingen.de
 * updates: mirror.rocketinternet.net
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package php-xml.i386 0:5.1.6-27.el5_5.3 set to be updated
--> Processing Dependency: php-common = 5.1.6-27.el5_5.3 for package: php-xml
--> Finished Dependency Resolution
php-xml-5.1.6-27.el5_5.3.i386 from updates has depsolving problems
  --> Missing Dependency: php-common = 5.1.6-27.el5_5.3 is needed by package php-xml-5.1.6-27.el5_5.3.i386 (updates)
Error: Missing Dependency: php-common = 5.1.6-27.el5_5.3 is needed by package php-xml-5.1.6-27.el5_5.3.i386 (updates)
 You could try using --skip-broken to work around the problem
 You could try running: package-cleanup --problems
                        package-cleanup --dupes
                        rpm -Va --nofiles --nodigest
The program package-cleanup is found in the yum-utils package.
[user@lnxcmsdev cms]$ sudo yum install php-common
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * addons: mirror.web-ster.com
 * base: mirror.hmc.edu
 * extras: mirror.hmc.edu
 * rpmforge: ftp-stud.fht-esslingen.de
 * updates: mirror.rocketinternet.net
Setting up Install Process
Package matching php-common-5.1.6-27.el5_5.3.i386 already installed. Checking for update.
Nothing to do

Идеи ??