Looking at the transcript posted by Chewett, it would seem the elf was unable to open the presents and did not know why there was a spell on the presents.
Therefore, I don't think we should be looking at the elf to solve this issue, but to the facts we know of.
We know the presents went missing and the elf was looking for them. The elf found them in 'Willow's Shop Locked Storage' and discovered they were protected by a spell. Ledah then killed the elf.
Which leaves us with several questions. What were the presents doing in 'Willow's Shop Locked Storage'? Who put the spell on the presents? Why did Ledah kill the elf?
Considering 'Willow's Shop Locked Storage' is locked and the shop is owned by Willow, it implicates Willow. Willow could have taken the presents and put a spell on them or had Ledah do it. This also explains the murder of the elf by Ledah, it was to prevent the elf from taking the presents back.
We should bring Willow in for questioning and, if necessary, torture him until we have our answers. (And Ledah as well)