I just tried the effect on Windows 7, and it works for me. So, let's try to figure out what's different for you.
Tell us some more about your computer system. Video card? Third-party video hardware?
Are you using OpenGL? If so, turn it off.
Does this happen in a new project with the effect applied to a solid-color layer? Or does it just happen in an existing project or with a specific kind of layer (i.e., based on a specific kind of footage)?
Is there any message that occurs when After Effects crashes? Does the crash reporter appear?
Thank you for your fast reply.
My Videocard is an Nvidia Gforce GTX480 (version 3.0.0)
I use a Matrox MX02 for video output
The only solution I found was to delete the directional blur plug from the plugs-in folder .
The problem happens randomly, when I try to use Directional blur on video layer.
Try on a system without the Matrox.
Probably a specific problem caused by the combination of graphics card and the Matrox stuff. Directional blur is an accelerated effect that can use OpenGL. therefore you may wish to set the "Accelerate effects using..." option in the prefs to Adaptive Resolution or turn off OpenGL entirely as Todd already suggested...
The "Unexpected data type" error bug and the crash with Directional Blur have been fixed in the After Effects CS5 (10.0.2) update.
Let us know after you've installed the update whether this is working for you.