I've started this thread as a question, but while writing it, I've got Scribus working, so I think it can help somebody else
I'm installing Scribus from Gslapt.
I' ve added the slackware repositorie, because I didn't find it in the default repositories. Updated de database
Selected SCRIBUS and installed it, even if Gslapt warned that gnutls was missing (requires version 1.6, and VL has a lower version)
Started Scribus, and didn't work
. Started from terminal, to see what happened:
"scribus: error while loading shared libraries: libgnutls.so.13: cannot open shared object file: No such file or directory"
So I reinstalled gnutls from Gslapt (just in case...)(perhaps it was updated, perhaps it's not necessary to reinstall....)
Made a simbolic link to /usr/lib/libgnutls.so.11.1.25 called /usr/lib/libgnutls.so.13
Started scribus again.
Now scribus is working. I don't know if some tools will not ..... I don't know what libgnutls does