It looks as though you need to change the file permissions on the files you untarred.
chmod -R 744 /home/epismen/public_html/mahoodle/mod/mahara-contrib-mdl19-mod-assignment-type-mahara/
And if that doesn't work, open it up further
chmod -R 777 /home/epismen/public_html/mahoodle/mod/mahara-contrib-mdl19-mod-assignment-type-mahara/
The 404 "Not Found" error and the error log are related.
You do not have a "500" page that shows up when a server misconfiguration occured, that caused the "404" page to show up.
I'd fix the file permissions first and see if that doesn't solve your other two problems.