very weird... do me a favor and try a regular (non-turbo) render, then open up "c:\programdata\squidyavi.bat" in notepad and paste the contents here. GIFsquid creates and runs this batchfile right after it renders the AVI. I want to see what it is trying to do. Note that c:\programdata is a hidden folder so may not be visible in explorer windows.
Here's what I found (used another project/comp, but same issue):
Successful (turbo):
cd\ cd "C:\Program Files\Adobe\Adobe After Effects CC 2017\Support Files\Scripts\ScriptUI Panels\GIFsquid\"
GIFsquidavi.bat 30 12000 "E:\Stephen\Documents\AfterEffectsProjects\WHATAMIGONNADO\Troi.avi" "E:\Stephen\Documents\AfterEffectsProjects\WHATAMIGONNADO\GIFsquid_Output" 0.5 800:-1 "" "Troi.avi" true
exit
Unsuccessful (non-turbo):
cd\ cd "C:\Program Files\Adobe\Adobe After Effects CC 2017\Support Files\Scripts\ScriptUI Panels\GIFsquid\"
GIFsquidavi.bat 30 12000 "E:\Stephen\Documents\AfterEffectsProjects\WHATAMIGONNADO\Troi.avi" "E:\Stephen\Documents\AfterEffectsProjects\WHATAMIGONNADO\GIFsquid_Output" 0.5 800x "" "Troi.avi" false
exit
Looking at the log file, now it's throwing new errors:
convert.exe: DelegateFailed `"ffmpeg.exe" -nostdin -v -1 -i "%i" -vframes %S -vcodec pam -an -f rawvideo -y "%u.pam"' @ error/delegate.c/InvokeDelegate/1919.
convert.exe: UnableToReadImageData `C:/Users/Stephen/AppData/Local/Temp/magick-31324qcORP4FuAA8U.pam' @ error/pnm.c/ReadPNMImage/1280.
convert.exe: NoImagesDefined `E:\Stephen\Documents\AfterEffectsProjects\WHATAMIGONNADO\GIFsquid_Output/Troi.avi-2018-04-12_21-04-51.gif' @ error/convert.c/ConvertImageCommand/3257.