The attachment indicates that you have an old version. Could you take a look at the modification time of /usr/lib/cups/filter/rastertogutenprint.5.1 and /usr/lib/cups/driver/gutenprint.5.1?
Also make sure that you're using the 5.1.0 PPD file, not the 5.0 one.
The attachment indicates that you have an old version. Could you take a look at the modification time of /usr/lib/ cups/filter/ rastertogutenpr int.5.1 and /usr/lib/ cups/driver/ gutenprint. 5.1?
Also make sure that you're using the 5.1.0 PPD file, not the 5.0 one.