ftp user limit to a folder

Hi
I need to create an ftp account that has access to a single folder only

I created a folder on root of domain called User_Folder
I then created an ftp account and set the folder to User_Folder

When I try to connect to this user Filezilla reports '421 Home directory not available - aborting'

If I delete the account and leave the folder as the default entry then I can connect, but then this account has access to all files and folders.

How can I create an ftp account that can only view and access a specified folder

Cheers
IDC