Bug: Export Snapshot to PNG Replace/Overwrite acts weird

Hey,

I think I just found a bug:

System: OSX 10.5
Mockups Version: 1.5.12

Problem: Overwriting an existing PNG file recursively re-creates the files path within the path. e.g. overwriting /foo/foo.png will create a new file in /foo/foo/foo.png instead of overwriting the file.

Steps to reproduce:

1) Open Mockups, new empty mockup layer shows
2) Add any element (lets say an Arrow)
3) Hit Mockup -> Save, save to /Users/felix/foo/foo.bmml
4) Hit Mockup -> Export Snapshot to PNG File (creates /Users/felix/foo/foo.png)
5) Repeat: Hit Mockup -> Export Snapshot to PNG File
6) Choose "Replace existing file"
7) File ends up being saved in: /Users/felix/foo/Users/felix/foo/foo.png

Hint: This may be related to: http://getsatisfaction.com/balsamiq/t...

Also: When I just tried reproducing this for reporting the bug I sometimes hit the case where I could not click either the "overwrite" nor the "create new file" buttons in the modal dialog which I worked around by restarting the app.

Quick help would be highly appreciated : ).
-- Felix