Iceweasel messing with video & screen flickering

[Bent Elbow <mrbentelbow@gmail.com>]

I using debian lenny 5.0 32 bit on my laptop
I installed the latest nvidia driver by the nvidia installer (it
compiled the driver into the kernel).
My video card is Quadro FX 1500M

Now, I have the following issue:
Whenever iceweasel is running, Kaffeine/mplayer either have black
screens (sound still comes), or
they play fine at the opened window size, but if I try to change the
window size, I get a black screen.

Also, a couple of times when both kaffeine and iceweasel were running,
suddenly many iceweasel windows got
green and black sripes arcoss them. The stipes disappeared when I
minimised and then unminimised them.
But then the entire screen started flickering.

My xorg.conf (I am running compiz):

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 1.0  (buildmeister@builder63)  Mon Mar 23
15:33:27 PST 2009

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
EndSection

Section "Files"
EndSection

Section "Module"
    Load           "dbe"
    Load           "extmod"
    Load           "type1"
    Load           "freetype"
    Load           "glx"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/psaux"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Unknown"
    HorizSync       28.0 - 33.0
    VertRefresh     43.0 - 72.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection


How can I fix this ?

Thanks