HELP! Cant make this a solid (only joined surfs)

 From:  Samuel Zeller
3237.1 
Hello everyone, here's a basic shape made from a loft. And a mirror
Its supposed to be a soap and there will be engraved text so I need to make this a solid.
I cant make one, I only have joined surface :( I dont see where there is a problem :(

Attachments uploaded.
Thanks for your help.
Attachments: