Can't Install Orca Forums or Opensocial Modules

This is the problem I'm having.

Orca requres PHP XSLT extension. Please enable it first then proceed with installation. 

For PHP4, make sure that PHP is compiled with the following extensions:

                    --with-dom --enable-xslt --with-xslt-sablot 
                

If these PHP extensions are enabled, then you can see domxml and xslt extensions in phpinfo() with the following options:

                    DOM/XML: enabled
                    XSLT support: enabled
                

For PHP5, make sure that PHP is compiled with the following extension:

                    --with-xsl 
                

If this PHP extension is enabled, then you can see xslt extensions in phpinfo() with the following option:

                    XSLT support: enabled
 

Opensocial requres PHP OpenSSL, mysqli and JSON extensions. Please enable it first then proceed with installation. 

To use PHP`s OpenSSL support you must also compile PHP --with-openssl[=DIR]. 
If you would like to install the mysql extension along with the mysqli extension you have to use the same client library to avoid any conflicts. 
To install the mysqli extension for PHP, use the

                    --with-mysqli=mysql_config_path/mysql_config
                

configuration option where mysql_config_path represents the location of the mysql_config program that comes with MySQL versions greater than 4.1. If you would like to install the mysql extension along with the mysqli extension you have to use the same client library to avoid any conflicts. 
To install the JSON extension for PHP, use the

                    --enable-json
                

shell_exec function is unvailable, this module require this function

                    --enable-json