Installing SPICE Guest Tools on Win XP Prof SP3 x86

I got troubles installing the SPICE Guest Tools on my win xp vm.
The installer loads just fine and states that it installed the program, but for example the shared clipboard does not work.
Also I can't install the WebDAV program from spice because "I don't have enough privilege". The manual from UTM states:

> The tools support Windows XP or higher on x86_64 (excluding Windows XP), i386, and arm64 builds.

What does that mean? First it is stated that Windows XP is supported but after that, it isn't anymore? Or ist only available on the i386 or the "real" x86?

Even a complete reinstall of the vm didn't help.
Any help is much appreciated, I'm really beginning to get desperate. UTM is looks really promising but it just doesn't work...