Luciano,
Sorry but it is a bug that we are aware of and did plan to have it fixed with the release of Flight Logger 3.0.7. The problem affects the 5 digit flights that were added for the opening of the KATL hub.
Unfortunately this has had to be put back as some problems were encountered when it went on public release at the end of last week.
Keep your eye on the news section for the new Flight Logger and this will fix your problem, hopefully it wont be too long with Bruno and Armando on the job!