The songs aren't compatible because they are formatted to the lg, not the samsung. The only way to get them to play is to save all your card files onto a computer then format your memory card to the samsung.. You format the card by going to settings and tools and look for the memory icon. This process will erase everything though thats why i said back it up 1st. Then you can load your card again. It's a pain in the butt but i know but it's the only way
Finally! Here's the deal ... when you are able to access the Samsung Rogue via USB cable and computer (figure this out from other posts), and you're ready to drop your music data into the my_music folder on the phone, it ONLY wants the song files and NOT all the folders. Rather then transfer the songs album by album, I did a search on the root folder for *.mp3 and later for *.wma files (I had both) and then selected all the found files (Ctrl A) and then MOVE (you can right click) them (if they're on the the micro disk) into the my_music folder on the phone. If you're transferring from an external source (C drive, etc.), just COPY the searched for files to the my_music folder on the phone. That way your song files will also stay on your computer.
After I disconnected the phone from the computer (you were using Tools / USB Mass Storage to get connected to your computer), I opened up My Music on the phone, hit options at the bottom and then did the scan. The scan of the music finally recognized the tracks and was then able to the sort them out by artist, genre, album etc. Problem solved ... but what a PITA. This ought to save some other Rogue users a lot of time and trouble. 