E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable)

This error message usually occurs when another process is using the package management system (e.g. apt-get, aptitude, or dpkg). To fix this issue, you can try the following steps:

1. Check if any other package management processes are running:

   ps aux | grep -i apt

If you see any processes related to apt or dpkg, you can kill them using the command:

   sudo kill <process_id>

2. Remove the lock files:

   sudo rm /var/lib/dpkg/lock-frontend
   sudo rm /var/lib/dpkg/lock

3. Update the package lists:

   sudo apt-get update

4. Install the package you were trying to install:

   sudo apt-get install <package_name>

If the issue persists, you can also try restarting your system and then attempting to install the package again.