Again, when posting, please provide pertinent information to provide more direct responses. Upon initiation of a new post, there should be "ghost" text already in the box identifying information that should be provided. As well with every post made there should be posting tips presented above the text box.
All that said, it would also help to read the plugin's notes:
MODERATOR NOTE: This module has been obsoleted by: http://www.zen-cart.com/downloads.php?do=file&id=400
This cross sell module has a graphical interface to quickly find products for cross sell. 6 cross sell products can set specifically set for each of your Zen Cart product pages.
Additionally this combo module has advanced cross sell which allows you to setup all 6 cross sells in the same screen using products numbers.
English version. NOT compatible for 1.3.X Zen Carts.
MODERATOR NOTE: This module has been obsoleted by: http://www.zen-cart.com/downloads.php?do=file&id=400
The first and last of which indicate that a different plugin should be used. As well, and though it does not always mean that it's a problem, the latest confirmed version of the software is for ZC 1.5.0. That said, if you are using ZC 1.5.0, besides being 5+ years old and in need of updating, the plugin should work. Now it is possible that a plugin not reported to work with a more recent version may work just fine as the related files may not have been changed since it was originally developed, or there may just be some minor changes needed to bring it up-to-date.
Whatever the case, also recognize that the people that post here do so when they are able and when they wish to. This is an open source, community run operation with what I believe are funds contributed to the developers (likely little), and through their sweat and sore fingers. :) Basically I'm reemphasizing that it may take time to publicly respond, and it is possible that a private response was provided to that last poster with no one adding to the discussion. Perhaps it would be more helpful to others if you were to add to that conversation based on what is learned here and/or beyond...
ZC Installation/Maintenance Support <- Site
Contribution for contributions welcome...