iFile allows you to email certain file types. It also allows you to open these same files if you receive them via email. iFile is one of my most favorite packages of all time and is one of the main reasons I jailbreak. Whenever that fails me, I use a combination of the DropBox integration with iFile and the Dolphin Browser to download any files from DropBox. Or I will use the actually DropBox app to download said files. It all depends on the situation. But either way, this is one workaround you could try using.
Edit: If you decide to use iFile you may have to set up a symbolic link so that your email contacts show up when you begin typing them in the mail app. If I remember correctly, iFile reads the root folder's contact database which is essentially empty. All of our saved contacts go to the mobile directory. It's either this or vice versa. But either way, if your contacts don't show up in iFile when sending an email, let me know and I'll give you instructions on how to set up a symbolic link so it will work correctly.