How do I make my table have full column rank?

Hi,

I am performing repeated measures anova on 14 subjects measured over 4 timepoints. I have 5 other grouping variables (demographic information such as sex, Genotype, Transplant) that I would like to include in the analysis. The problem is, when I enter

V=ranova(fitrm(V,'x1-x4~Treat+Sex+Genotype+Transplant+PreviousTreat','WithinDesign',Time))

where Time=(1 2 3 4)

I get

Error using RepeatedMeasuresModel.fit (line 1331)
The between-subjects design must have full column rank.

Error in fitrm (line 67)
s = RepeatedMeasuresModel.fit(ds,model,varargin{:});

How do I fix this?

Thanks