Hola siempre que intento descargar, actualizar, instalar algo con el magento conect me sale este error y no se de que es.. gracias por su ayuda

Did not download optional dependencies: pear/XML_RPC, use --alldeps to download automatically
Magento Downloader
Exception caught:

Warning: popen() has been disabled for security reasons in /home/novamix/public_html/tienda/downloader/pearlib/php/OS/Guess.php on line 247

Backtrace:

#0 /home/novamix/public_html/tienda/downloader/pearlib/php/OS/Guess.php(247): mageCoreErrorHandler(2, 'popen() has bee...', '/home/novamix/p...', 247, Array)
#1 /home/novamix/public_html/tienda/downloader/pearlib/php/OS/Guess.php(159): OS_Guess->_detectGlibcVersion('/usr/bin/cpp /t...', 'r')
#2 /home/novamix/public_html/tienda/downloader/pearlib/php/OS/Guess.php(114): OS_Guess->parseSignature()
#3 /home/novamix/public_html/tienda/downloader/pearlib/php/PEAR/Dependency2.php(105): OS_Guess->OS_Guess(NULL)
#4 /home/novamix/public_html/tienda/downloader/pearlib/php/PEAR/Downloader.php(259): PEAR_Dependency2->PEAR_Dependency2()
#5 /home/novamix/public_html/tienda/downloader/pearlib/php/PEAR/Downloader.php(501): PEAR_Downloader->getDependency2Object(Object(PEAR_Config), Array, Array, 4)
#6 /home/novamix/public_html/tienda/downloader/pearlib/php/PEAR/Downloader.php(409): PEAR_Downloader->analyzeDependencies(Object(PEAR_Config), Array, Array, 4)
#7 /home/novamix/public_html/tienda/downloader/pearlib/php/PEAR/Command/Install.php(629): PEAR_Downloader->download(Array)
#8 /home/novamix/public_html/tienda/downloader/pearlib/php/PEAR/Command/Common.php(285): PEAR_Command_Install->doInstall(Array)
#9 /home/novamix/public_html/tienda/downloader/Maged/Pear.php(234): PEAR_Command_Common->run('install', Array, Array)
#10 /home/novamix/public_html/tienda/downloader/Maged/Pear.php(301): Maged_Pear->run('install', Array, Array)
#11 /home/novamix/public_html/tienda/downloader/Maged/Model/Pear.php(244): Maged_Pear->runHtmlConsole('install', Array, Array)
#12 /home/novamix/public_html/tienda/downloader/Maged/Controller.php(128): Maged_Model_Pear->installPackage(Array)
#13 /home/novamix/public_html/tienda/downloader/Maged/Controller.php(350): Maged_Controller->pearInstallPackagePostAction('magento-core/Ma...')
#14 /home/novamix/public_html/tienda/downloader/Maged/Controller.php(170): Maged_Controller->dispatch()
#15 /home/novamix/public_html/tienda/downloader/index.php(35): Maged_Controller::run()
#16 {main}