Thanks for your comments to everyone. I finally managed to spot the variable
in each round that was causing problems to complete the transfer from SPSS to
STAta. I have to say that both variables (one dichotomous and one continuous)
seemed to have no problems in the case number where the transfer process was
stopping. Any thoughts on how to test any further problem with them despite
the unsuccessful initial exploration? Just as a reminder, the message
displayed was Invalid Floating Point Operation.