Access Violation at startup when launched via Shell Extension

Thanks for this excellent program. I'm very happy having found it.
When I try to launch via the shell extension (i.e. right-click on a folder for example), the dialog to select files/folders appears and after that I get an error:

Access violation at address 008E78A8 in module 'ARen.exe'. Read of address 00000008.

Then, the main interface appears, but without the files/folder added. Leaving this open and right-clicking again and selecting 'Add to advanced renamer' adds the files. There is no error when the app is already running and then using the shell extension.

I'm using Windows 8 Pro 64-bit.

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