Your Seller Admin > Edit Affiliate Program Settings apply in common to all products in your account; it's not possible to exempt any specific products from that. However, you can leave your common affiliate share set to 0%, then go to Seller Admin > Setup Product Specific Affiliate Programs, select a product you do want granting commissions and click Edit Affiliate Settings, then specify the share percentage affiliate-referred sales of that product.
This help page explains more about our affiliate settings:
http://www.e-junkie.com/ej/help.affiliates.htm
If you don't want a product listed for sale in your E-junkie Shop at all (these product listings are also shown when existing E-junkie affiliates search our site for other programs to join), just go to Seller Admin > List products in your E-junkie Shop & Marketplace, select the product and click Add/Edit Listing in E-junkie Shop & Marketplace, then delete its Details and click Next. Shop listings are optional; they are not necessary if you are selling products from your own Web site.