Korg Poly800/EX800 Users

i recently aquired a slightly beat up poly 8.  aparantly whoever was
using it before didnt realize you needed to keep the batteries in to
hold the memory onboard.  the tape input jack became so worn i had to
replace it (which i did).  ive made an attempt to reload the sounds
back onto the system but i cant get a good message after verify or
load.  im playing the sounds off my computer and right into the
system.  it seems to only load about the first 20 or so sounds then
gets corrupt in the later catagories, 30 - 88.  does anybody have any
more information about loading.  i notice the text flickering when i
load up sounds is that normal?