Installing packages during installation

[2creativelab]

OS: Ubuntu 12.04
Plesk 11

Hi all,
I have a problem during installation when plesk wants to install more packages from apt.

385 packages need to be installed. 49 packages need to be updated. Sycronizing index file of Debian APT package...
ERROR: An error has occured while PREP actions performing

I translated from italian. Official error string could be different.

Does someone can help me? Plesk does not give any error code. Simply it says that installation process has aborted.

Thank you so much!