server - problem when reinstall apache2 ubuntu 14.04

I had some problem when reinstall apache2.

I use:

sudo apt-get install --reinstall apache2 apache2-bin

and then error with this messages,

/etc/init.d/apache2: 64: .: Can't open /etc/apache2/envvars
/etc/init.d/apache2: 76: .: Can't open /etc/apache2/envvars
ERROR: APACHE_PID_FILE needs to be defined in /etc/apache2/envvarsinvoke-rc.d: initscript apache2, action "restart" failed

I try to purge use this:

sudo apt-get purge apache2

after that I try to reinstall again use this:

sudo apt-get install apache2

This is message when I try to reinstall apache2 use that code:

    Reading package lists... Done
Building dependency tree       
Reading state information... Done
Suggested packages:
  apache2-doc apache2-suexec-pristine apache2-suexec-custom apache2-utils
The following NEW packages will be installed:

  apache2
0 upgraded, 1 newly installed, 0 to remove and 405 not upgraded.
Need to get 0 B/87,5 kB of archives.
After this operation, 473 kB of additional disk space will be used.
Selecting previously unselected package apache2.
(Reading database ... 170080 files and directories currently installed.)
Preparing to unpack .../apache2_2.4.7-1ubuntu4.1_amd64.deb ...
Unpacking apache2 (2.4.7-1ubuntu4.1) ...
Processing triggers for man-db (2.6.7.1-1) ...
Processing triggers for ureadahead (0.100.0-16) ...

Processing triggers for ufw (0.34~rc-0ubuntu2) ...
Setting up apache2 (2.4.7-1ubuntu4.1) ...
Enabling module mpm_event.
cp: cannot stat ‘/usr/share/apache2/default-site/index.html’: No such file or directory
dpkg: error processing package apache2 (--configure):
 subprocess installed post-installation script returned error exit status 1
Processing triggers for ureadahead (0.100.0-16) ...
Processing triggers for ufw (0.34~rc-0ubuntu2) ...
Errors were encountered while processing:
 apache2

E: Sub-process /usr/bin/dpkg returned an error code (1)

Can somebody please help me to solve this problem?

You can see what dpkg complaining about,

sudo dpkg --configure -a
sudo apt-get install -f

try to run the following command

sudo apt-get remove --purge apache2 apache2-utils

then run,

sudo apt-get install apache2