First off if you get an error it is always worth checking the error stream of the process, which will contain any output to the command line regarding errors; and alternative in this case is to simply open the command line run command and look at the output.
In this case your problem is that:
CMD wrote:
The system cannot find the file specified.
In Server 2008 the recycle bin is now located at $Recycle.Bin so you want to use
rd /s/q \$Recycle.Bin
in that case. There is however another gaping flaw here, on my machine I have a couple of HDD's and I keep the recycle bin on my drive
D:\
so while the command would run fine it wouldn't actually empty my recycle bin. You would have to run the command on drive
D:\
(rather than the defauly
C:\
)
You might want to look into other ways of emptying the recycle bin.