This was my concern, as well, and that's why I mentioned it. However, I just looked at the Spanish version of the site-- where the disclaimer is more precise:
"Bonificaciones adicionales de millas de viajero frecuente por compra en línea no aplican a estas tarifas." In other words, they appear to be referring specifically to ineligibility of these fares for an on-line purchase bonus.
Hagbord Viking, Dividend Miles is a U.S. Airways FF program. TACA also is a participant in KLM's Flying Dutchman program, which states clearly that its members are able to earn credit for all flights on Latin Pass member airlines (including TACA).
[This message has been edited by HKG_Flyer1 (edited 12-26-2001).]