Some new songs don't appear in listing

[UPNext]

Hi, I am running the 4.001 version of Microstudio and it has been working great except for one weird thing. I recently added some new songs to my Hoster Database and when I browse the directory that they are in only some of them appear in the Microstudio listing. I can play all of the songs using Hoster and I double checked that they have been imported into the correct directory. I'm at a bit of a loss as to why this would be happening. Does anyone have any ideas?