I have just recently upgraded PHP 5.3 to 5.4 on my Debian Squeeze server. Now, instead of executing PHP files, Apache just downloads them, which is really bad.

When I try to follow these steps, I get "broken packages" upon installing the libapache2-mod-php5 package.

Also the answer tells me to add something to my httpd.conf, but it's empty.

Question: How can I make apache execute php files again, instead of just passing them through as download?

dpkg -l | grep php returns this

rc  libapache2-mod-php5                 5.3.3-7+squeeze15            server-side, HTML-embedded scripting language (Apache 2 module)
rc  php5-cli                            5.3.3-7+squeeze15            command-line interpreter for the php5 scripting language
ii  php5-common                         5.4.15-1~dotdeb.2            Common files for packages built from the php5 source
rc  php5-gd                             5.3.3-7+squeeze15            GD module for php5
rc  php5-mcrypt                         5.3.3-7+squeeze15            MCrypt module for php5
rc  php5-mysql                          5.3.3-7+squeeze15            MySQL module for php5
rc  php5-suhosin                        0.9.32.1-1                   advanced protection module for php5
rc  phpmyadmin                          4:3.3.7-7                    MySQL web administration tool

And apt-get install libapache2-mod-php5 produces this error

The following packages have unmet dependencies:
 libapache2-mod-php5 : Depends: libdb5.1 but it is not installable
                       Depends: libssl1.0.0 (>= 1.0.0) but it is not installable
                       Depends: libxml2 (>= 2.8.0) but 2.7.8.dfsg-2+squeeze7 is to be installed
                       Recommends: php5-cli but it is not going to be installed
E: Broken packages