Cracking sound in 2 sec gap

i,m getting a cracking sound in the 2 sec gap with the latest version of plextools pro using the audio cd maker. did the same tracks with the latest nero and it was fine. might this be a bug with plextools? any ideas? any help would be appreciated.

oops, i forgot to mention that i have a 24/10/40a plex drive set up as master, a liteon cdrom ltn 403 as slave.
i messed around some more with it and if i create a cd with the audio cd maker from mp3 files (creating an image first) there is no popping cracking sound in the 2 sec gap, but it is certainly there when doing it from wave files.
i think it is weird that it is only in the gap between songs the songs are perfect. again nero does it from mp3’s or waves perfectly. so maybe i just have something screwed up or it may be a bug. i thought maybe someone was having a similar problem or could give me some insight. thanks