As steeldriver says, this is not a question that you answer interactively. Instead, it is a reminder that you must run commands like
aptitude as root, for package installation to succeed.
If you're not running it as root or are not sure if you are--in particular, if you are not using
sudo--then you should run it as root with
sudo. See this question for more information:
If you are using
sudo but still get that error, that's strange. There are some similar errors can occur when permission to access a lock file is denied due to another concurrently running package management utility or stale locks (that continue existing after the utility they represent is no longer running). So some of the answers here may help:
If none of this helps, then you'll have to provide more information. In particular, to get better answers, you should add the complete and exact text from the Terminal, including the lines showing commands you are running (and especially the command or commands that result in the "are you root" message), to your question, by editing your question.