I believe in the original CrossSell mod you need to add certain files into "includes", and edit some other files. Check to make sure that you have it set correctly.

Then in you admin->configuration->cross-sell check this:
You will see that you have 2 settings with the same name "Display Cross-Sell Products" (I should have changed those names, in fact I will do in the next version)
The first "Display Cross-Sell Products" is the minimum number of products required to display cross-sell, make sure you set this to 1

The second is the maximum number, set it to whatever you want (i.e: 8)