I'm trying to download the old multiDll ZIP (i need ChilkatUpload_x64.dll). However the zips are 404'ing here: https://www.chilkatsoft.com/downloads_ActiveX_multiDll.asp
That is a very old page (the downloads listed are dated 11-Mar-2014). The page is also not linked from the official download page ( https://www.chilkatsoft.com/downloads.asp ).
The very last and final build/version for the multi-DLL ActiveX's are available at the links below. Each .zip contains all of the DLLs. I erased the entire web page (referenced above).