using R's amelia to deal with missing values
You could use th R program Amelia to impute numeric variables. We use 10 iterations to determine how to fill the missings. R needs some power and it might be necessary to make serveral rounds or use a bigger machine. One idea is in order to find rules to elimiate missings, but of course they also could contain valuable informations and you want to preserve and interprete them. The results of R's Amelia will be stored in a CSV file in the temp folder of the system. Shown are methods to determine the paths and give them to a CSV reader.