"not signed with a trusted certificate or one of its components."?

[nicolasod]

Con algunos de los programas que quiero ejecutar en mi htc touch 3g clon aparece este mensaje y no puedo instalarlo, sale cuando quiero instalar el pocketGBA, el morphgear y programas similares de emulacion, "the file xxx cannot be opened. either it is not signed with a trusted certificate, or one of its components cannot be found. If the problem persists, try reinstalling or restoring this file.

Espero quem e ayudespor facor, saludos.