Board Thread:Lua Help/@comment-5068292-20150131070710/@comment-3298582-20150202130109

Ok. I guess the error has something to do with the way modules are loaded by.

First undo the last replacement in Module:Citation/CS1/Date_Validation I suggested. Then copy the method  from Module:Citation/CS1 to Module:Citation/CS1/Date_Validation. Insert it above the comment starting in line 36.