Phone Playing Wong MP3 File.

I have about 600 MP3 files on my microSD card, organized in about 100
directories. My Series 40 6133 phone is detecting all the files, but when I
select from the tracklist a file above 256, the wrong MP3 file gets played.
The problem may be related to the maximum size of the track list. I was
unable to create another track list. I was unable to add or remove files
from the track list. The manual does not cover this subject, internet
searches returned fruitless. Please Help.