EXS 24 Logic Sampler Users Group

I bought a few Akai sample cds which i convert in my
EXS24. when chosing them from the flip menu right after
the conversion of the cd is done they play back just fine.
As soon as i turn my computer off the mess begins:
After every reboot, the initially perfectly converted
samples get lost! Sometimes more than 75% of the sample cd
it's content gets lost. I always get the following error
message: "EXS instrument"name".exs"
         "audio file "name.wav" not found
If i check the lost file it's properties it's OK,
the file is still in place and the properties of it
do not differ from the audio files that do play back!
I have an EXS24 sample cd "xtreem analog" from emagic 
which never loses it's files, so i guess the problem is 
located within the few Spectrasonics cd's i have and with
it's akai conversion. While troubleshooting i reinstalled
a few of those cd's,yet again...same symptoms.The cd's take
up to 100 minutes to convert each! Now i'm looking for a 
solution :-)
PS: I got lots of HD space left, so that's not it