Canon iP4600: filter error on Ubuntu

[Pete Bowler]

Have just bought and installed an iP4600.

Have installed the drivers and the system recognises the printer OK. Installation gave the message
dpkg - warning, overriding problem because --force enabled:
package architecture (i386) does not match system (amd64)
which is odd because I have a 64-bit Intel chip (x86_64). However, it seems to accept it.

Unfortunately when I do a test print, I get:
/usr/lib/cups/filter/pstocanonij failed

Is this a problem with the printer or CUPS?

I had a similar error with my old HP Deskjet 310 (thought it was because it was too old):
/usr/lib/cups/filter/foomatic-rip failed

Can anyone help?????????????