I had DUPLICATED the normal patch inside the EXTRA folder by mistake, instead putting there the additional patch. With this update that is fixed.
Now the normal patch and the optional patch inside EXTRA folder are different; the second does really replace the enemy names by the Spanish names used in modern translations of Dragon Quest series.
It has been an human mistake.
By some reason that I don't know the patch of DRAGON QUEST 1+2 was CORRUPTED.
It needs to be downloaded again.
I was generating the patch with SNESTOOL and it produces some kind of incompatibility when expanding this ROM. I have generated it with LunarIPS; anyway, it works with both tools now.