(EDIT: looks like I’m unable to open nor save .SLA files with this – which is not particularly useful. Stay tuned…)
(EDIT #2: see here for the workaround)
This has taken me an age to complete, but I’ve had success in the last hour.
My bug report is here. In summary, on Ubuntu Linux (for example) the latest development builds of Scribus have no problems with the Qt packages available from the (Synaptic) default repositories. On OpenSolaris however, this doesn’t seem to be the case with Qt packages available at http://solaris.bionicmutton.org, as I’ve discovered after many hours fruitless tinkering.
I’ve found that I can build Scribus 1.3.6.svn successfully, using Qt 4.6.2 as built from source. Thankfully this is a pretty straightforward (albeit long) process.
Details covering package prerequisites etc are now here.