On Verifying/Reparing DIsk Permissions i got the following errors
Veryfying Volume "Macintosh HD"
Checking HFS Plus Volume
Checking Extents Overflow File
Checking Catalog File
Checking Multi-Llinked Files
Checking Catalog Hierachy
%)
Chgecking Extended Attributes File
Checking Volume Bitmap
Checking Volume Information Volume Header Needs Minor Repair
The Volume Macintosh HD needs to be repaired.
Error.The Underlying Task reported failure on exit
Have you by chance turned on Debug mode for your dock?
Either way,
Try a Reboot, then Repair.
If that doesn't work try to zap the P-RAM, reboot then repair. (though I am not sure that this portion of the Desktop is in the Pram, it may release locked resources that could be affecting it )
::EDIT::
Darwin has a great point. Didn't think about that!