I've got the same problem. Well, not exactly the same. My google map will only show 11 points but these come from 3 different record sets, so it is not a recordset problem, per se. No errors in the javascript console and viewing the source I don't see anything out the ordinary. All of the points are in the generated javascript. Could it be a google limitation? I have another application (without webassist) where I show 100 points on a google map and that still works.
Mine also is PHP/MySQL
http://www.londonbeerguide.com/map.php
Added: It is not an address problem -- my three recordsets have 11, 4 and 4 records. The 11 recordset one was first and that was all I got. I deleted it and added it back on the end, now I get the 4+4 and only the first 3 of the large recordset.