SQL Server Database Not Shrinking
I'm going to make a wild guess and say that your database is set up to use FULL recovery.  You have never taken a log back up (let alone a full one) based on the image above.  If this is the case then you log file is growing and growing and can't clear out because you haven't taken a backup.  

If you have the room take a full backup, then a log backup and try your shrink again.  Should work fine. 

Worst case (and I do mean worst, particularly if this is a production database) is to set the database to SIMPLE recovery, shrink and then take a backup.  This should work even though you don't have enough space for a shrink normally.

At this point make sure you set up regular backups for your database.

You can go here for more detail.



EDIT: 

Can you tell us what % free the log is vs the data file?
Also you might look at the log_reuse_wait_desc in sys.databases.

SELECT name, log_reuse_wait_desc FROM sys.databases 


And last but certainly not least have you tried the TRUNCATEONLY option of shrink?

DBCC SHRINKFILE (Adventureworks2008R2_Log, TRUNCATEONLY)