--- Operating System, Graphics card ---
Windows XP
Ati Radeon HD 4800

--- Blender version with error, and version that worked ---
Version 2.66 - r54697

--- Short description of error ---

First bug:
In Object mode:
1. Add a cylinder mesh;
2. add a plane mesh;
3. boolean modifier on plane mesh
4. operation "difference", object "cylinder" then apply.

The result is not a "perforated" plane, as expected. See attached figures.

Second bug:

Boolean modifier between two plane (any operation) crashes the system. Try:

In Object mode:

1. Add the first plane mesh, grab and scale it;
2. Add the second plane. The planes are of course at the same z-coordinate (z=0);
3. Select first plane, add a boolean modifier (any operation, for example "intersect"). Object: the second plane

...the system crashes.

Best regards.



--- Steps for others to reproduce the error (preferably based on attached .blend file) ---