Thank for for giving me access to one of your source images and for letting me know what settings you are using.
(I have deleted the login details from your post above and you can now delete the temporary FTP account on your web server.)
I have been able to replicate the problem and it looks like the error is triggered by certain values for the large image settings.
This is not a problem with your image. For example, with your own image, if I set the Large Images Max Width and Max Height to both 2507, the image is processed correctly. However, if I use values of 2508, the error message is displayed.
Thank you for pointing out this problem. I have notified the developers who will certainly investigate further.
In the meantime, it looks like the workaround would be to reduce your Large Images Max Width to 2507 (or lower).