Recently many users reporting deb package installation error using Ubuntu Software Center On Ubuntu 11.10 Oneiric Ocelot. So here are a couple of ways to install deb package instead of using Ubuntu Software Center.
Installation deb package might be corrupted which will cause the error as well. I had the same error while trying to install Google Chrome stable release using Ubuntu Software Center. According to the reported bugs by many users on launchpad about this issue, internal error happens for some users because the home directory is encrypted, however not many users confirmed that.
Installing deb package using Terminal
Run Terminal “Ctrl+ALT+t”
sudo dpkg -i "package name"
Quick guide for installing and removing deb packages.
Install deb package using gdebi
First you will have to install gdebi tool.
sudo apt-get install gdebi
Then right click on the package you want to install and select gdebi package installer.
Launchpad Bug “Software Center cannot open external .deb file google-chrome-stable“.