I'm finally stumped at to why I continue to get this error.

I am running ZCS 6.0.6 with Thunderbird 3.1.0 on Windows XP connected via IMAPSSL. I am trying to copy a 17MB email from my local machine to a directory on Zimbra. I've followed everything I could find about the "maximum message size exceeded" error and the "maximum request size exceeded" error but to no avail. Here is what I have tried so far:

zmlocalconfig -e imap_max_request_size=1073741824 
zmlocalconfig | grep -i imap_max_request_size
imap_max_request_size = 1073741824

zmprov modifyConfig zimbraMailContentMaxSize 67108864
zmprov getConfig zimbraMailContentMaxSize
zimbraMailContentMaxSize 67108864

zmprov modifyConfig zimbraFileUploadMaxSize 67108864
zmprov getConfig zimbraFileUploadMaxSize
zimbraFileUploadMaxSize: 67108864

zmmailboxdctl restart
I successfully copied a 7.3MB file to the same destination on Zimbra. Any ideas?