Well there is some kind of workaround. It seems that if you click on the red X it doesn't carry over all the Characters or spaces.
So in the meantime you might as well try to rightclick on the red cross and save the shortcut.
Then you open up a new Browserwindow and paste the link into the address bar. Should work then...I hope
If that doesn't work then in the new window you need the following in the address bar
h**p://yourserver.com:adminport/DELETE_CLIENT.TSCMD?client=
( it is shortening URLS in here )
then behind the = you simply copy the name from the listing with all spaces and characters and hit enter. This way you get around the confirmationpage that seems to cause this behaviour.