Question: When one opens the dialog for Table information, the lower half shows "Information about the corresponding media directories" including a column for 'Entries'. Where does this number come from? 
Answer :  This is the number of files located in the table's sound directory that have the following extensions;
MUS, WAV, RAW, AIF, BWF, MPG, MP2, MP3, RTF.
This behaviour will most likely be handled differently in DBM version 3.0 because an entry can consist of multiple files.