Software :: Unable To Install Any Package In Ubuntu (10.04)

When I try to install any package in ubuntu (10.04),it gives the error message. Suppose I am installing vlc it gives:

Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run `apt-get -f install' to correct these:
The following packages have unmet dependencies:
gstreamer0.10-plugins-bad: Depends: libflite1 but it is not going to be installed
vlc: Depends: vlc-nox (= 1.0.6-1ubuntu1.8) but it is not going to be installed
Depends: libqtcore4 (>= 4:4.6.1) but it is not going to be installed .....
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).

Then I did.
sudo apt-get -f install
It too gives the error as:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Correcting dependencies... Done
The following extra packages will be installed: libflite1
The following NEW packages will be installed: libflite1
0 upgraded, 1 newly installed, 0 to remove and 429 not upgraded.
1 not fully installed or removed.
Need to get 0B/7,274kB of archives.
After this operation, 10.6MB of additional disk space will be used.
Do you want to continue [Y/n]? y
E: Invalid archive signature .....
E: Sub-process /usr/bin/dpkg returned an error code (1)