Hi Dsahala,
Kindly try our suggestions for this type of problem here:
http://forum.brillkids.com/little-reader-bug-reports/pronunciation-audio-getting-cut-off-please-see-here/I would recommend that you try the first one (i.e., update your computer's codec), and if it doesn't work try the rest of the suggestions there.
If you are still having problems, do tell us about it in more detail, and you may also send us a Diagnostic Report (see link below for instructions on how to do this):
http://forum.brillkids.com/little-math-bug-reports/