I have never installed Kaspersky, but Avast says on startup, Kaspersky is installed
and therefore disables the main scanner providers.
Now I searched for the file “KLIF.Sys” as described in http://forum.avast.com/index.php?topic=12079.15.
On my system this file is in the following folder: C:\WINDOWS\system32\ZoneLabs\avsys
so it seems it belongs to the ZoneAlarm Security Suite wich I have installed - and not to Kaspersky.
Is there any possibility to manually tell Avast that it should start the main scanner providers?
The security suite may be using kaspersky for one of its modules, if it is AV (the path you have provided would tend to confirm that) and it is resident then two resident AVs can cause conflict and that is why avast is objecting. Having two resident scanners installed is not recommended as rather than provide twice the protection it can cause conflicts that could leave you more vulnerable.
I believe kaspersky also did and anti-hacker application which used the same name as the main kaspersky program, but that doesn’t appear to be the case. There is no way to tell avast to start the main providers, it is trying to avoid a conflict that could lock up your system and then you wouldn’t be too happy.
You need to disable/uninstall the AV module in ZA Security Suite, it may even require an uninstall, reboot and custom install without the AV module.