In the process of learning a bit more about how OpenMX works and getting up to speed on twin study methodology, I have been running some of the presentation scripts from the Boulder conference's intro seminar. I'm having a bit of a problem with one of the scripts for binary outcome twin models and was hoping that someone recognized the issue. The script I am using is here: http://ibg.colorado.edu/cdrom2010/rijsdijk/OrdinalTwinAnalysis/Binary/Un... 
Everything appears fine (after changing the script to remove protected characters) until I attempt to run the TwinSat model. I am getting an error message that states: "Error: In model 'twinSat' column 'cast90_tw1' is not an ordered factor. Use mxFactor() on this column."
Normally, I would just follow the instruction, but looking at the data, it appears that the only responses in that column are 0 and 1. So, using mxFactor would, if I understand it correctly, not change any of the values. I know the conference was in March, so there may have been updates to the package since then that require this step, but I didn't want to get into the habit of doing this every time if it isn't necessary.
Thanks in advance for all of your help!