In case you didn't figure out the issue yet, you don't have the folder (or images) for the assembling machine 3 so you are pointing to files that don't exist, causing a problem with any mod that would try to do something with that machine.
I managed to fix this type of error by making the assembling machine 3's definition in prototypes/entity/assemblerpipes.lua point to the assembling machine 2's images instead.
Not sure if it was just an issue caused by copy/paste or if you didn't add the images (if you wanted the pipes to be different for tier 2 and 3).
Also not sure if it's something you did or not but apparently I wasn't able to drag the modfied file into the zip to replace yours like I usually do for other mods when doing manual fixes, it corrupts the whole zip file and it can no longer be read.
I had to extract the mod instead to be able to apply the changes (again not sure if it's something you did or if my computer decided that it wanted to do weird things with that zip file).