A) Try to disable avast self defense module and restart notebook several times, until all avast! Firewall NDIS Filter Miniport entries or unknown devices will be gone from device manager.
B) If this does not helps, uninstall avast, restart, install avast, restart and disable self defense.
A or B should solve avast! Firewall NDIS Filter Miniport problem, if it's related with your problem directly, this workaround should solve it.