problem starting prius

i recently have problem with starting my Prius.once i jump start it. it start immediately and  
it shows red warning triangle light on to dash board and green led light on parking button
fleshing.some time they doesn't go away though car is going fine. i have japan made car
so can't read the warning which come up on the display. i went to mechanic too he put
some device under neath steering but no code was found and he remove thing warning
sing by using that device. now this thing happen two time in last two day. today i was able
to rid of those sing by moving the gear stick randomly to N D and R. it doesn't give me
problem in starting in the morning but it just randomly doesn't start. i called AA roadside
service today and guy said some how battery is drained. He wasn't able to tell me cause
of it. now this happen about 5 time s in this monpth. so i am not sure why my battery is
getting drained or its some thing else. i am using my car as taxi and my modem,camera
etc attached to 12 v battery. but its there for last 7 month and i don't think it would be
because of  those stuff.as i never have problem before . please help me with this.. .