I am getting same thing. InfoPath reports Submit was successful but I do not see anything in my list.
I am using Infopath 2007 and Moss 2007 Enterprise
Here is my CAML
<?xml version=''1.0'' encoding=''UTF-8''?>
<Batch OnError=''Continue''>
<Method ID=''1'' Cmd=''New''>
<Field Name=''Title''></Field>
...