Error php 5.4 installation

Hi,

I try to install php 5.4 on my plesk serveur with the web interface but it return me an error.

The apg-get failed with the following message:
Reading package lists...
Building dependency tree...
Reading state information...

When i try to install it with command line, it return this message.

---X--- `apt-get` output ---------------------
Reading package lists...
Building dependency tree...
Reading state information...

---------------------- `apt-get` output...

Error php 5.4 installation