Sansa e250 not showing new music on player

[homerus]

I have a sansa sandisk e250 and i am having problems putting music on and pulling music off of it, all the files are in .mp3 format.  Here is exactly the example of whats happening:

I Pulled Pink Floyd - Echoes folder and all songs off the player database out of the music file
I put Pink Floyd - The Wall folder into the music folder in the database

I try to play the files but they are not showing up at all, and the Echoes File and all the songs still show up in the database but i cant play them because i took them off, is there something i am missing here?  please help!!!

[AlexP]

Do you have the database set to update?

Or have you tried to update it manually?

[homerus]

that worked great, thanks!