Make sure you are aware that your home directory and your ~/Maildir directory each reside on their own volume, and each has a separate quota. If you are logged into an HCoop machine, quotadisplay will display your used space and quota for all of your volumes.
Before copying files over, be sure that you have enough disk space in your quota using fs listquota ~/.
This will give you the name of your volume, available space (in KB), used space (in KB), the percentage of your volume used, and the percent of space used on AFS by all HCoop volumes.
If you need more space, please file a quota change request using the portal.