error 99

I'm currently using MediaLab v.2004 and I'm having some problems. Some of the data in SPSS comes out with straight "99" across all variables, though that's not a possible value. We thought it might be due to participants clicking through too fast, but that gave us normal data. Then we tried running the program, clicking CTR ALT DEL to shut it down, and then running under the same participant number, but that still didn't give us the 99's. Why are some of them 99? We can't seem to figure it out.

99 is used as the default missing value. You could get all 99's if you were to skip all the questions/questionnnaires. Even if you do so, the data are still recorded.