The problem is not with MultiProxy, but with one of the proxy servers in your list. Just test each proxy one by one and delete all proxy servers that alter the pages that you visit. I have found a couple of sites which seem to somehow be able see through the MultiProxy shield and detect my correct IP address. And since these applets run on your local machine, proxy server will not protect you. The only way is to disable Java and ActiveX controls in your browser.
Proxy servers are wonderful.
Originally used by companies to speed up web browsing for its employees, they have evolved into something a little more useful for the home user. Finding a fast, reliable one can be quite a challenge. We can do that. I went through a Japanese proxy one time and was fed banner advertisements written in the same. I couldn't read them, but I felt like I knew martial arts, so I went out and picked a fight with some local ruffians.