installing roundcube

we want to install roundcube and it is giving an error Fatal error: Class 'PEAR' not found in /share/MD0_DATA/Web/roundcubemail-git/program/lib/Roundcube/[login to view URL] on line 101 and we try to install needed parts [/share/MD0_DATA/Web/roundcubemail-git] # ipkg install php-pear Installing php-pear (5.6.33-2) on /opt/. Downloading [login to view URL] Installing php (5.6.33-2) on /opt/. Downloading [login to view URL] Configuring php. Configuring php-pear. //opt/lib/ipkg/info/[login to view URL]: line 12: 28811 Segmentation fault /opt/bin/php $PHP_FLAGS $PEAR_BOOT_DIR/[login to view URL] $PEAR_FLAGS mv: unable to rename `/opt/etc/[login to view URL]': No such file or directory [/share/MD0_DATA/Web/roundcubemail-git] #