Note:

This problem was fixed with Service Pack 0, released in May 2012. Please check, if you have downloaded the latest version before you started the installation.
In case this problem persists, please contact our support team, referencing to article Id: 1087.

The error message "Scheduler not loaded" appears during an update. This suggests damage to your installation and can only be fixed by a thorough uninstall and reinstall of your Avira product.

Please proceed as follows:

1. Download the Avira RegistryCleaner of the type "exe" on your desktop or a folder of your choice.
   Caution: Do not yet execute the file!
2. Additionally, you can download the most current version of your product:
   
   Avira Antivirus Premium 2012
   Avira Internet Security 2012
   Avira Free Antivirus
3. Uninstall your Avira product by clicking on Start and then Control Panel > Uninstall a program (for XP: Start > Settings > Control Panel > Add or Remove Programs).
   Select the Avira product from the program list and then click on Uninstall (in XP: Remove)
   
   
   
   Now, please restart your computer.
4. After the reboot, you should delete any remaining files of Avira.
   
   To do this, click on Start > Control Panel > Appearance and Personalization> Folder Options. By clicking on the tab "View" you will find in the section "Hidden files and folders" the option "Show hidden files, folders and drives". Activate it and click on OK.
   
   In XP, you will find the "Folder Options" at Start > Settings > Control Panel. Here you should activate the option "Show hidden files, folders, and drives" in the tab "View" at "Hidden files and folders".
   
   
5. Please delete now the following folders:
   C:\Program Files (x86)\Avira
   C:\Documents and Settings\All Users\Application Data\Avira
6. Execute the file "avira_registry_cleaner_de.exe" that you have previously saved on the desktop or a folder of your choice.
   Click on the button Scan for keys and confirm the completed scan with OK.
7. Activate the control box at "select all" and then click on Delete. Confirm the next query with OK. Now, please restart your computer.
   
   
8. After the restart, run the installation file that you have just downloaded and follow the instructions.
   As you reach the dialog of the license wizard, you need to enter the activation code; alternatively you can use your license file with the format HBEDV.KEY. Once the installation is complete, restart your computer.

However, if this procedure does not work and you still need help, then please contact Support, quoting the number of this KB-article (in this case 1087).