File error - in NW-E003 SONY MP3 WALKMAN

MP3 players can only play music files in mp3 file format. You need to convert your CDs to mp3 music files onto yourcomputer or download them from the Internet and then copy them to your MP3player.
You can do this using Windows Media player and Rip the CDs - Media Player willcreate a MP3 music file for each music track.
Click on this link for instruction on converting music files to mp3 file format:-
http://www.fixya.com/support/r5798418-creating_transferring_mp3_music_files

Ya sure its virous attack in this immediately format it and check with latest and updated anti virous and may be brother now you have to update software for itself

I downloaded a compatible program with vista, and now my mp3 player works great again!!!!

Please format your walkman

if it happens with one single song it's because the file type is not formatted, you'll need to convert it (try mp3 :) if it happens with all of your songs first try checking their type if it's okay, try formatting your walkman and putting new songs

sony walkmanmodel no nw e105 write no data what can l do

my sony walkman mp3 player model # NW-EO15F i cannot upload any songs, i wanna upload songs. but i don't know how to upload songs.please can you tell me.

Take a look at this tip/trick.
I think that would solve your problem.

Install the player cd into your pc and then transfer the song through the software.

I hade just that prob. "format error" used to display. I did this:
1. dwl sonicStage (free)
2.- in the walkman went to menu/initialize/format
then displayed a confirmation screen, I confirmed
it displayed "formating...... COMPLETE"
3.- THEN plugged into the PC and transfered songs with Sonic
and it worked!