[Duplicity-talk] Understanding "Aborting because you may have accidentally..."

[address@hidden]

I am using duply + duplicity to backup my local machine.

The last backup I ran was a full backup (the second full backup to my backup directory). Today I am trying to run an incremental backup, but receive this error instead:

"Aborting because you may have accidentally tried to backup two different data sets to the same remote location, or using the same archive directory.  If this is not a mistake, use the --allow-source-mismatch switch to avoid seeing this message."

Does anybody know what this is about? I read the manual but am still a bit confused on what I am doing wrong.

Thanks in advance.