Which scans exactly give the error? Most likely what you have is just an incomplete download, when using a download mamanger make sure not to use multistreaming, it will result in incomplete downloads. Either only make one connection per download or just download the comics manually by clicking on the link, and then waiting for it to finish downloading before downloading the next comic.
Edit - I checked and it does seem like there is an error with the files, we might need to have prime user check the originals and upload them again if they are OK.