Can you view svg files with Ristretto?

[Sergio]

> 
> Sorry - both are using nvidia cards and drivers, but the
> work machine
> is Intel (dual Xeon quad-cores with 10GB memory) and the
> home base is
> Phenom II X6 with 16GB memory, and obviously different
> motherboards....
> 

I don't think that interferes.
It works just fine here (ristretto 0.6.0) with an image I downloaded from 
http://www.esds.ac.uk/qualidata/online/data/edwardians/downloadphotos.asp

I think that with upgrades maybe the settings files for ristretto changed format and that broke it.
Try something more comprehensive like besides those files cited before, also remove/rename .cache/sessions .cache/Thunar and .local/share/recently-used.xbel*