yes indeed! there was an error with the naming of the config file for ptrotanki´s safeshot mod.
protanki renamed the config file from "safeshot" to "saveshot" and it was my bad, that i didnt checked that while updating the mod!
now this is solved and should work as intended when installing again (beta database, not pushed to public now, but you can choose it in the modpack settings)!
regarding your other errors in python.log: i dont think battle observer is the main suspect, maybe some sound mod....
if the error still persists, can you send us the lastinstalledconfig.xml from your relhax directory (RelHaxUserConfigs-folder)?