Win7, 64bit.
Avidemux v2.7.1
Attempted to open .py file (File > Project script > Run project). Result was failure and crash. Details attached.
Closed program and tried again several times with same result: failure and crash.
Each retry got crash file message; choosing yes (load crash file) got tiny py exception message, followed by shutdown upon pressing OK.
admlog.txt you've attached has been generated by Avidemux 2.5.6.
The most likely cause of the crash is source video missing at the location specified in the .py script.
"admlog.txt you've attached has been generated by Avidemux 2.5.6."
Interesting, since that version isn't even listed on my computer's list of installed programs.
If it is not installed now, it might have been either installed or run as portable app at some point in the past. 2.7.x writes the log to %localappdata%\avidemux\admlog.txt, so if you grabbed the file from another location, it may originate from an old version.