Be sure you are running Hoster 4.05. Or... wait about another week and we expect to release 4.06 with several bugs fixed. You can download free upgrades from
http://www.mtu.com/upgrades/hoster.htm
marklwood is correct. If you read
http://www.mtu.com/upgrades/hoster.htm#V402 #6 item, you will see we are converting your HDZIP (KMA) files to HDMP3G. This is so Hoster doesn't have to unzip them, which is a variable amount of time. This variance has been causing problems, and will cause great problems when we introduce "crossfading" from one song to the next.
Also in
http://www.mtu.com/upgrades/hoster.htm#V404 #20 we further refined this.
When Hoster now runs, it scans your Songs Database. If it finds any HDZIP files, it presents a dialog for you to convert them to HDMP3G.
You are not yet REQUIRED to do this, and Hoster will still play HDZIPs if they have not been converted. However, the day is coming when HDZIPs will no longer play.