Error In PHP5 ..Unable to load dynamic library

Even though several other answers suggest it, installing more unnecessary software is generally not the best solution. Instead, you should fix the underlying problem. The reason these messages appear is because you are trying to load those extensions, but they are not installed. So the easy solution is simply to tell PHP to stop trying to load them:

First, find out which files are trying to load the above extensions:

$ grep -Hrv ";" /etc/php5 | grep -E "extension(\s+)?="

Example output for Ubuntu:

/etc/php5/mods-available/gd.ini:extension=gd.so
/etc/php5/mods-available/pdo_sqlite.ini:extension=pdo_sqlite.so
/etc/php5/mods-available/pdo.ini:extension=pdo.so
/etc/php5/mods-available/pdo_mysql.ini:extension=pdo_mysql.so
/etc/php5/mods-available/mysqli.ini:extension=mysqli.so
/etc/php5/mods-available/mysql.ini:extension=mysql.so
/etc/php5/mods-available/curl.ini:extension=curl.so
/etc/php5/mods-available/sqlite3.ini:extension=sqlite3.so
/etc/php5/conf.d/mcrypt.ini:extension=mcrypt.so
/etc/php5/conf.d/imagick.ini:extension=imagick.so
/etc/php5/apache2/php.ini:extension=http.so

Now just find the files that are loading the extensions that are causing the errors and comment out those lines with a ;. For some reason this happened to me with the default install of Ubuntu, so hopefully this helps someone else.

sudo apt-get install php5-mcrypt
sudo apt-get install php5-mysql

...etc resolved it for me :)

hope it helps

Look /etc/php5/cli/conf.d/ and delete corresponding *.ini files. This error happens when you remove some php packages not so cleanly.

Seems like you upgraded PHP to newer version and old .ini files are still pointing to old location.

The solution: find out where are modules located now

ls -l /usr/lib/php5

There should be a directory similar to old 20090626. In my case it is now 20131226

The .ini files giving you an error are located at /etc/php5/cli/conf.d/

Just edit those .ini files which module gives you an error. For example, in case the error is for mcrypt module:

sudo vi /etc/php5/cli/conf.d/20-mcrypt.ini

Change the line:

extension=/usr/lib/php5/20090626/mcrypt.so

to reflect the new path for .so file. In my case the correct path should be:

extension=/usr/lib/php5/20131226/mcrypt.so

That's it! The error is gone. Ofc you'd have to do it with each module giving you an error.