iTunes 10.5.2 rips tracks with noise/crackle to NAS server

This weekend I installed my Synology DS-212j NAS-server and migrated my iTunes library to it with the intention to have my entire iTunes library on the NAS. When I ripped some CDs in iTunes to the NAS, I noticed that the files have noise/crackle on the beginning and on the end of the WAV-file.

When I opened the ripped files in my Wave-editor the noise/crackle was visible just before the track starts and just after the track finishes on the left channel of the stereo wave. When I rip tracks to my old iTunes library located on one of the drives in my Mac Pro there is no noise/crackle.

Does anybody have an idea what could cause this problem and how it can be solved? I have tried to google it but didn't find any similar posts.

I run Mac OS X 10.6.8 on my Mac Pro with iTunes 10.5.2. The Synology NAS has 2x Western Digital Caviar Green 2TB drives (WD20EARX) inside.

Any help would be greatly appreciated. Thanks in advance!

Danny