Could you post all steps to create this.
You could find at help file
Creating silent installation of avast! program
This option, intended especially for network administrators, makes it possible (and easy) to install avast! on an arbitrary number of computers, without any interference from the users. The installation may contain predefined settings of the program and tasks.
To create the silent installation:
1. Install avast! on one computer.
2. Modify the avast! settings exactly as you want them to be on the other computers.
3. Set the parameters of the tasks (as you want them).
4. If you wish, set the password to access the resident protection settings (and termination).
5. In the Enhanced User Interface, select File ® Create Silent Installation.
6. Set the parameters of the silent installation:
Silent mode - During the installation on the target computers, only error messages will be displayed.
Very silent mode - During the installation on the target computers, no messages will be displayed.
Installation path - Enter the folder to install avast! to (by default, %PRGFILES%\Alwil Software\Avast4).
No reboot - avast! requires the computer to be restarted after the installation. If you select this option, the reboot will not be requested.
Ask for reboot - When the installation is finished, the user will be asked to reboot.
If neither No reboot nor Ask for reboot is checked, the system will be restarted automatically when the installation is finished.
7. Click the Create button.
8. Select the folder to store the files necessary for the silent installation.
9. The following two files will be written to the selected folder: admin.ini and tasks.xml. The file admin.ini contains the settings of the avast! program, the file tasks.xml contains the settings of the particular tasks. If the password for resident protection settings was set, there will be another file in the target folder: aswResp.dat; it contains the encrypted password to access the resident protection settings and termination.
10. Put these two or three files into a shared folder.
11. Put the avast! installer into the same folder.
12. On the target computers, start the avast! installation from this folder.