I upgraded KDE to 3.2.1 version and then after the installation I use swaret to check for any missing library:

# swaret --dep kde

Listing missing Packages...
Search for (libusb-0.1.4), needed by 'kdegraphics-3.2.1-i686-1'!
Search for (libusb-0.1.4), needed by 'kdegraphics-3.2.1-i686-1'!

But I've already have libusb-0.1.8 installed. I have libusb-0.1.8-i486-1.tgz
Swaret did not detect it because it's a i486 package ??
I could not find it for i686 arch.

Another question
Did I do it right? I mean, for checking missing libraries, after the installation, should I do it with swaret?

Here is the way I did it and it worked first time out: (slack 9.1)

swaret --set VERSION=current
swaret --update
swaret --upgrade kde -a -ap
This will install kde and all dependencies. Just make sure your swaret.config
is set to check dependencies.
Hope this helps.