I get an error from CHDK-Shell-v346.exe with trunk4233.zip and trunk4234.zip.
trunk4231.zip works fine.
As noted in the commit message for r4232
https://www.assembla.com/spaces/chdk/subversion/commits/4232Building in the CHDKShell GUI will be broken. Building form the command prompt launched by CHDKShell should work.
I understand this is inconvenient, but digic 6 support is necessary for the long term future of CHDK. CHDKShell will likely be updated to support this at some point.
In the mean time, you can launch a command prompt from chdkshell (the C:> icon) and type
make PLATFORM=<your camera platform> PLATFORMSUB=<your canon firmware> clean fir
If you want to build a zip, use firzipsubcomplete instead of clean fir.