What exactly is this kind of issue? It pops up everytime i reboot! Im using SnowLeopard
View attachment 607194
The popup tells you exactly what the issue is. You have a system extension that is improperly installed. That can be the result of copying a kext file from another Mac, or copying the file directly from a backup.
The popup also tells you that it can't use (and therefore won't load) that extension.
Your example shows a USB Ethernet network driver, usually for a USB to Ethernet adapter.
It's an Apple kext (part of the installed OS X, so the fix is simple:
Reinstall Snow Leopard from your original installer. When that completes, run your Software Update until it no longer shows available updates..
Another fix to simply get rid of that window, if you don't use a USB to Ethernet network adapter - delete that file. The popup tells you where the file is located, so you can just drag it out to the trash. You will have to authenticate to do that. (If you don't ever use a USB to Ethernet adapter, you can choose to ignore that missing .kext file, unlikely your system would ever miss it!)