To assign the Web Services permission to a role:
Step 1: Go to Setup > Users/Roles > Manage Roles.
Step 2: Locate the role you want to modify. Click the corresponding Edit or Customize link.
Step 3: Click the Setup subtab, in the Permissions dropdown list, select SOAP Web Services.
Step 4: In the Level drop-down list, select Full.
Step 5: Click Add.
Step 6: Click Save.