Please verify a few things:
1. Have you followed all the steps from the web scheduler documentation when you install it? Please make sure that you've run the activation step after the installation.
2. Please verify if web component is working properly. You can run the validation wizard for that. In OCS admin tool, navigate to the machine that runs web component (IIS), right click and select validation->Web Component server. Please make sure the check the “View the log when you click Finish” at the last screen of the wizard. In the web browser screen that shows the log, you will find out where the log file is. Please post back with the log file.
3. Please verify if the user you logged into the above URL is enabled for communication. T check that, in OCS admin tool, navigate to the OCS pool, and click on users, the user you used should be listed.
Thanks!