Thanks for reporting. I'm really surprised by this error, but I could reproduce it easily when I download the AI through BaNaNaS and start RailwAI.
If I extract the .tar file that was downloaded by openTTD to the AI folder, RailwAI starts without any problem.
If I take a look at the .tar file, it seems that openTTD writes 3 bytes too much for the file shippathfinder.nut. Usually this wouldn't matter because of zero-padding in the tar-files, but in this case BaNaNaS generated no zero-padding here
I have opened an issue on GitHub about this bug in OpenTTD.
Luckily I'm not dumb and with a slightly different file length, BaNaNaS does more zero padding.
Changelog for version 11 (a lots of updates lately):
- Bugfix: verify if a train is in the way to build a tunnel properly
- Small changes in pathfinder for ships
- Slightly fewer buoys are used
- Workaround for a bug in OpenTTD that made this AI not downloadable through OpenTTD