Dear freesurfer user,

I'm new in this freesurfer and i want to analysis of the thickness of two groups, dementia and normal.
I was trying to use qdec but when i pressed "analyze" button, there was some message at the bottom, which is "Error during design creation". 
At the same time, on the terminal, the following message came up.
"ERROR: QdecGlmDesign::Create: zero factors! "



For details, See below.

Please let me know what the problem is.

Thanks.

M.J. 

------------------------------------------------
Reading /Applications/freesurfer/tktools/tkUtils.tcl 

Using /Applications/freesurfer/lib/tcl/fsgdfPlot.tcl  

Loading data table /Applications/freesurfer/subjects/qdec.table.dat... 
Number of columns:  3 
fsid column:        1 
Number of factors:  2 
Number of subjects: 10 
Reading discrete factor levels from config file /Applications/freesurfer/subjects/diagnosis.levels
            AD
            Normal 
done.  

Data table /Applications/freesurfer/subjects/qdec.table.dat loaded. 
Verifying subject data..........Subject verification complete. 
Input table: /Applications/freesurfer/subjects/qdec.table.dat 
Subj#, SubjID, Data...    
 1 a1002 AD 75.000000      
 2 a1003 AD 63.000000      
 3 a1009 AD 71.000000      
 4 a1015 AD 80.000000      
 5 a1019 AD 75.000000      
 6 n1004 Normal 72.000000      
 7 n1005 Normal 71.000000      
 8 n1006 Normal 57.000000      
 9 n1007 Normal 62.000000     
10 n1008 Normal 62.000000  
1  diagnosis  discrete 2     
     1  AD      
     2  Normal 
2  age  continuous 0         
         Continuous Factors:         Mean:       StdDev:                
                      -------------------         -----       -------                                
                                      age        68.800         7.361  

Number of subjects:   10 
Number of factors:    2 (1 discrete, 1 continuous) 
Number of classes:    2 
Number of regressors: 4 

============================================================ 
Data table loading completed successfully. 
SUBJECTS_DIR is '/Applications/freesurfer/subjects' 
ERROR: QdecGlmDesign::Create: zero factors!