What version of MediaLab are you using (2008.x.x)? If you have a recent version then also check to make sure the variable name is the same as it is labeled in the data file output. You could also check to make sure the variable is always entered in lowercase wherever it is referenced in case there is an upper/lower case issue (unlikely but possible). If none of this helps, please zip and post or email me a sample I can look at--I'll see if I can reproduce the problem.