Hi Dawn,
Firstly make sure the carriages are positioned properly and that the Connecting arm is seated correctly on the main carriage.
Then check that you have the correct setting 'P' or 'H' on the ribber. 'P' is the setting to use when you have alternate needles in work on each bed, it can also be used for circular knitting because only one bed knits at a time. 'H' is for Half Pitch - when you are using adjacent needles on both beds, for example full needle rib, in fact whenever the needles would hit each other if you left the setting on 'P'. For some rib settings you cast on using 'H' then change to 'P' to knit the rib.
Hope this helps.
Sue, October 2009