You have to "Sign Up" for the PC Tennis Elbow 2011 Tour first. To do so, go to the main page of ITST:
http://www.intertopspintour.net/index.p ... &gc=PCTE11.
There, click on "Personal Page", it will look similarly to my page:

Then click on "Change User Profile" and on that page check the box next to the tour you want to play, in this case PC Tennis Elbow 2011 (and in my case there is still PS3 Top Spin 4 there):

Finally, on that page, click on Submit and you should be able to sign up for TE tournaments.