Hiss from speakers playing animated Dreams

Dear Support,

I bought DeskScapes 3 two Weeks ago and i've a little but annoyng problem:

The program rocks and works very well, except for a hiss in the speaker while using animated dreams.
The problem is a hiss in background that not depends from audio volume, and occurs with ALL animated dreams, videos hybrid and dynamics one, even the included in the installation.

The hiss is audible until 1 meter from speakers (very annoyng) and stop only deactivating the animated background and using a normal wallpaper, even set up from inside deskscapes, not necessary from Windows 7 control panel.
So the problem is for only Animated Dreams with or without audio, Videos, Dynamic and Hybrid, not for wallpapers.

My OS is Windows 7 ultimate x64 genuine.
The audio card is an external professional audio card Echo Audiofire 4 wired into the pc via Firewire.
All my drivers are up to date.

here my info:

--------

Your computer has a Windows Experience Index base score of 5.9
Your Windows Graphics Experience score is 7.8

DeskScapes appears to be activated on this PC
DeskScapes engine appears to be running
(Dell 3008WFP(Digital)) 1 is attached to NVIDIA GeForce GTX 295
(Dell E248WFP(Digital)) 2 is attached to NVIDIA GeForce GTX 295
(Generic PnP Monitor) 3 is attached to NVIDIA GeForce 9500 GT
(Dell E248WFP(Analog)) 4 is attached to NVIDIA GeForce 9500 GT

Deskscape.dll               2009/11/18 16:35:27
Deskscapes.dll                2009/11/03 18:56:35
DreamControl32.dll              2009/11/09 09:43:17
DeskscapesConfig.exe               2009/12/17 20:34:45
UI\Deskscape.dll             2009/11/11 13:21:12
UI\DeskscapesVideo.dll      2009/10/24 18:04:54
DreamTasks.exe                2009/11/09 22:10:57
DeskscapesVideo.dll           2008/02/15 22:10:44

Hope the problem is solvable

Kind Regards