I would format the card with your Blackberry first (if it was already preformatted or you did it on your PC), then copy the mp3's back onto it (usb cable or adapter shouldn't matter).
Alright, I'm stumped! The files I copied over are showing up on the phone as m4p files, while the ones that i already had on my phone that DO work are m4a files and one mp3 file. Media Manager is not giving me the option to convert the files, only to copy them. These are songs from my itunes folder, if it matters.
If you want to look into removing the DRM, you can check out this or this.
Also, I don't know how itunes works, but if it lets you burn your music to a CD.. you can always burn it to a CD (CDRW so you don't waste it) and then rip mp3s from the CD. A more involved and longer solution, but maybe another possibility.
Hmmm.. well I guess that's what happens when you write software that breaks DRM. LOL.
I guess you could always try the other thing (if you can burn CDs in iTunes) or if you just need a few songs for your ringtones, I'm sure I can find MP3's of them for you.
I had an issue similar to this too. After I did a batter pull it worked fine though. Pretty sure you already tried that though. Just this goat's two cents.
Posted from my CrackBerry at wapforums.crackberry.com
Well I think maybe (and I know nothing about iTunes, so I'm sure I'm wrong) but maybe the ones that are m4p, that don't work (and can't) are ones you paid for, which is why they have DRM... and maybe the m4a ones that do work were free downloads (which is why they don't have any protection)? Just a guess since I have no idea how iTunes works. Would that make sense? If iTunes has free downloads that is.