Differential backup fails if Backup location exists as zip-archive (Toucan 2.0.7)

If you have made a backup (and set "Backup location" to a zip-archive like "Jan.zip") and then wants to make a "Differential" backup, the process fails.
You get this information:

Starting...

Time: 07:28:56

Creating file list, this may take some time.

7-Zip (A) 4.65  Copyright (c) 1999-2009 Igor Pavlov  2009-02-03
Scanning

Creating archive D:\Jan.zip\BaseFile.zip 

Compressing  treeinfo.wc

Error:
move file error
D:\BaseFile.zip .tmp1
D:\Jan.zip\BaseFile.zip 
The system cannot find the path specified.

System error:
Unspecified error

Time: 07:29:16

Elapsed: 00:00:20

Finished

There is a need for a check on the "Backup location" to see if a folder with the desired name can be created.

Otherwise I like the application more and more.
Thanks
JC