Device not responding during file transfer

My device is Samsung GT-I9305, I've been using AirDriod for months and I didn't experience any glitch until a few days ago. I mainly use Airdriod to tranfer video files which are approximately 120~220 Mb in size. About a few days ago, i can fire up airdriod and start transfer files normally but the progress bar will stop at 24% ~ 90%. The bottom right indicates "Device Not responding". Please note that my phone is either left idle for like 15 seconds or I kept using my phone to prevent it from sleeping, but nothing works, airdriod keeps telling me the "not responding" message regardless my effort to keep my phone awake.
Please help

oh, i used Chrome version 27.0.1453.116 m. when i switched to firefox it worked perfectly.