Ark and unzip as well extract 'non working' files from this zip files.
<Unzip -t -v> results in ' No errors detected in compressed data'. Okular complains that the extracted pdf file doesn't exist and so does calligra with the doc files.
After some testing, it seems to be a matter of creating 'non-existing characters' in the name of the files. After renaming them (in cli), they are opening faultness as expected .
By instance: an uncompressed attachment file in hotmail has the name 'Trinité.doc'. After download in zipped mode, and after decompressing, the name has changed to 'Trinite??.doc'. In gui mode, it is not possible to change this name ('file doesn't exist'). After renaming via the cp command in cli (with automatic name completion for the strange characters), the file opens in the expected way.
Edit: I've tried the same sequence with the same post and same attachments under ubuntu 14.04 LTS (another computer). Also here the zip extracts in files with changed names (addition of 'strange' signs), but here these files are opening without renaming.