1. You should activate the session cookies of your browser to make the login work. In order to activate your session cookies please go in your Internet Explorer. Above in the toolbar you can find the button "Tools". There you choose the "Internet Options". Afterwards you select "Privacy".
More secure solution (recommended)
2. a) Now you go on the button "Sites" and enter the Domain "www.ido-dance.com" into the white field. Afterwards you choose "allow" on the right. Please affirm with "OK", twice, close the Internet Explorer and reopen it.
2. b) (not recommended) Now you go to "extended /expanded", enable the checkboxes "accept all cookies" and "allow per-session cookies". Please close the Internet Explorer now and reopen it.