Find the following code in members.asp (around lines 131-133):
if srchInitial = "1" then
tmpSQL = "M_NAME LIKE '" & SearchName & "%'"
end if
and change it to (or add the green code):
if srchInitial = "1" then
tmpSQL = "M_NAME LIKE '" & SearchName & "%' AND M_NAME<>'n/a'"
end if