I live in England and I have tried De Zelfde Method in the past and it did not work for me either. Personally you must enjoy your learning and that way you will learn more. Perhaps this class is just not right for you. My mother was not Dutch and she did not teach me Dutch and I was annoyed with her for years and when I was 21 decided to go to classes and she just made fun at me and that put me off. For a number of years I did beginner classes as it was so hard to get any higher in the area where I lived in the Uk so in the end just gave up. It was not until my mother died 3 years ago when I decided I wanted to have another try and this time it worked. Because like someone has said above there is no so much more help via the Internet that was not there years ago so "real Dutch people" in Holland can help those like me
To my surprise I found a Dutch Language School in Oxford that was run by a native Dutch teacher and her correspondence courses are fantastic. After me completing the beginners course I could actually start to speak Dutch... I am now on my third course doing GCSE which is a UK based qualification and I take my exams in May. The one area these courses lack are in talking and prouncation so 8 weeks ago I had another look round the Internet and found Yorien - a Dutch teacher from Grongingen who teaches over skype and who does a simple but brilliant and fun email course and very cheap (39 euros for 6 lessons I think). I also having a 20 min talking lesson with her every week and my prouncation has really improved so I am hoping when I get my mock exam with my teacher in Oxford in a couple of weeks time she will notice the difference. She tells me that my Dutch is good.
Perhaps doing a simple email course would be good for you as altough you work through it at your own speed it is fun and simple grammar is also involved in the course and its full of soundbytes and real dutch conversations. If you are interested you can find her at http://www.sayitindutch.com
It has already been said above one method is not right for everyone. The important thing is that you learn by whatever method is good for you. And a tip..... this site is so much helpful for learning too. Try some of Jokes lessons in the audio area as they are brilliant. If you do any writing etc one of the natives correct it for you. I have learnt so much from them and I am sure you will too. I would be interested to hear how you get on. I pop on the forum every day