It appears that the "us" entry from the hr symbols file is missing an include 
"us" which makes the keyboard unusable.

Attached patch fixes it.

--- hr-old      2006-03-20 22:26:35.000000000 +0100
+++ hr  2006-03-20 22:25:50.000000000 +0100
@@ -10,6 +10,8 @@
 partial alphanumeric_keys
 xkb_symbols "us" {

+    include "us"
+
     name[Group1]= "Croatia - US keyboard with Croatian letters";

     key <AD01> { [    any,    any,     backslash               ] };