Problem with (hammer?) noise

It's my first post so hi everyone.

Well I'm new pianoteq user (with no much knowledge about piano construction), I've made my song and everything is fine except one annoying thing.

In the background I can hear some kind of percussion noise (knocking?). I want to erase that and only keep a piano melody. I've tried to decrease "hammer noise" to 0.20 bu it isn't working. When i'm changing other things the tune of melody is different;/

So I wonder if there is any change to erase that noise without interference on melody.

Here is an extract, the noise is audible at 0:02 and also later;/

http://www.mediafire.com/download.php?mzzyootdymy

Thanks for any help.