Digital Workshop

Hello, I have build application for android with 28 images that also have a sound for each image, first time I access the application from android device everything works fine all the sounds works on Left Mouse Click trigger also if I repeat 2 times it also works fine but when I close the application and access it again then only some sounds works but not all some times 5 sound other times 3 and so on, is it a bug with android OS or other bug.
Thanks
aiad