PROBLEM : when I make a correction on any file, in a few minutes begins flashing

Hi all.
I have a problem, when I make a correction on any file of any origin, not instantly, but in a few minutes, begins flashing, both the monitor output, as the projector as the monitor window in the software.

I Have This configuration:

2009 8-core Mac Pro 3.1
Quad-Core Intel Xeon 2.8 GHz
16GB RAM
OSX 10.6.7
slot 1: Nvidia 4000
slot 2: Red Rocket
slot 3: Deck Link Studio
slot 4: SAS

Deck Link Studio 3G SDI to SDI OUT IN BM UltraScope (In Another Computer)
BM UltraScope Out to SDI HD Link Pro 3D
HD Link Pro 3D via Display Port to HP LP2480zx
Deck Link Studio HDMI OUT to Panasonic AE4000

And also try this other configuration:
slot 1: Nvidia 4000
Slot 2: NVIDIA 120GT
slot 3: Deck Link Studio
slot 4: SAS

And I have the same problem.
I also tried without the projector.
Please need help urgently.

Alejandro Matus
Digital Cine Rent
http://www.digitalcinerent.com