MacBook does not sleep when lid is closed
A lack of wake reason entries suggests your Mac is never fully sleeping. The sleep mechanism has started but never completes.

Use the following Terminal command to view a detailed log showing your Mac's power history:

pmset -g log


You will see a list of entries in form:

 * Domain: applicationresponse.slowresponse
 - Message: PMConnection AirPort configd plug-in com.apple.powermanagement.applicationresponse.slowresponse 1399 ms
 - Time: 13/03/2012 12:27:53 CET 
 - Signature: AirPort configd plug-in
 - UUID: AB482838-2D6E-0000-0000-14BF53E20000
 - Result: Noop
 - Response time (ms): 1399


Look out for applications that may be keeping your Mac awake and active. Applications and other processes can keep your Mac awake if they are providing a service, such as file sharing or remote access. However, processes should be forced asleep after 30 seconds on lid close.

The behaviour you are seeing suggests a kernel extension or IOKit problem. User level processes can not block sleep when instigated by the user.

Do you have any utilities installed that install kernel extensions (kext)? These might include screen recording or audio capture tools; utilities than need low level access to your Mac.