Hi piladzisi, can you kindly email us at support[at]brillkids[dot]com and include a few more details:
1. Which specific file isn't working for you - if possible, do provide the download page or the full title of the file so we can test that file
2. Please send us your diagnostic report. For instructions on how to create a report, you may refer to this article:
http://support.brillkids.com/entries/20438423-How-to-Create-a-Diagnostic-Report-for-your-BrillKids-Learning-SystemThere might be a bug or an error in either the file itself or in Little Math v2, so we need to troubleshoot to find the root of the problem.
We look forward to hearing from you!