diff --git uc_signup.module uc_signup.module
index dd241d2..24a1eb8 100644
--- uc_signup.module
+++ uc_signup.module
@@ -542,7 +542,7 @@ function theme_uc_signup_confirmed_signups_text($signups = NULL, $admin = FALSE)
  * nodes when the 'Skip checkout for free events' setting is disabled. 
  */
 function uc_signup_signup_suppress($node) {
-  if (isset($node->sell_price) && $node->sell_price > 0 || !variable_get('uc_signup_skip_checkout_free', 1)) {
+  if (uc_product_is_product($node) && (isset($node->sell_price) && $node->sell_price > 0 || !variable_get('uc_signup_skip_checkout_free', 1))) {
     return TRUE;
   }
 }