The 'moodle march' hasn't been easy for many. Glad I could help with that.
So it's only the Spanish course backups that fail? That seems to suggest an issue with language supports.
http://docs.moodle.org/25/en/Language_packs
In 2.5, filters, Activity names auto-linking is auto on, if I re-call correctly. Have any other filters on? In 2.5 there is one for Multi-Language Content. Is that on? Might have to arrange them differently ... ie, move upwards in the filter list Multi-Language Content such that it's above Activity names auto-linking.
Offer: have a sandbox site (a 2.5.x) where you could be granted access and attempt the restore there. I could then inspect all that one normally can't/won't see in the Moodle UI. IM me if interested.
'spirit of sharing', Ken