Hi,
I take it you're running into issues installing SQL Express?
If so, try the following:
1. Stop the AV running on the server and disable it.
2. Run the installation again. If it completes, great...
3. If not, try copying the SQL Express installation folder to a local drive. Once done, run the SQL Express installation, and once it completes, then run the Backup Exec installation.
4. Start up the AV services again.
THanks!
EDIT: You can also download the Microsoft MSI cleanup utility. Run that and see if there are any SQL installations on that server, and if so (and if they are NOT in use), uninstall them with the utility. Then try running the application again.
Also, make sure the account being used to install the application is a local admin, and that the account that will be used for the BESA is a domain admin.