Video files will not play

When trying to view files over network answer is yes.  They simply will not play.  Same files will play (most of the time) when it is the 1st file reflected on the USB drive.  I can not select subsequent files.  I have a later version of the WD TV Live and it works.  I understand some avi files won’t work and I’ve been able to convert them to something which will work.  This problem is associated with the older model only.