For one whose first language is not English, you write very well! Your application letter presents clear ideas on why you wish to be accepted into EUR's International Business Administration Program, as well as a good summary of your background and interests. This is a good first draft.
In order to arrive at a polished letter that you will reflect your very best effort, may I suggest that you consider two general steps in your current drafting process: (1) Editing and (2) Revising.
Editing is the simpler of the two drafting processes, as it consists of correcting typos, misspellings, grammar and usage, etc.
Revising is definitely a more involved part of the drafting process, as it calls upon judgments concerning (among other things) sentence and paragraph structure and organization, as well as the writer's own unique style.
To make this easiest for you, may I suggest that you first focus on the editing part of the process To help you with this I will cut & paste your current draft below, providing corrections, which I will boldface, as well as any comments, which I will Italicize, to help your understanding.
After you've made these editing corrections to your first draft, I will be glad to help you with suggestions for revising that will lead to a final draft of your letter. Please note that revising your letter may require several more drafts. Only you can decide when you fell confident about a final draft.
Below is your first draft with my editing corrections:
Dear Sir or Madam: (This is the correct convention for a business letter salutation. As far as etiquette goes, it's usually ladies before gentlemen, but in a business letter salutation, the convention is "Dear Sir or Madam:" Please note the colon in place of the comma that you used -- a comma is appropriate for a personal letter but not a business letter.)
I am hereby applying for entrance for the International business administration program at the Erasmus University Rotterdam (EUR) in September 2009. (Space added here.) In the following letter I will explain why I think that the EUR is the ideal university for me.
First of all I would like to start with information regarding my background. I was raised in a small town called Kaifeng, (In English, proper names are always capitalized.) situated in the middle part of China. When I was 10, my parents made me come into contact with English (Again, proper names are always capitalized). Later, in (Omit the article "the" here) middle school, I realised that I was a quick learner and English rapidly became my favorite and best subject.
In (Again, omit the article here.) middle school, I started to get involved in school politics by being elected as president of student council. Although designing and managing activities such as debates, sports games, (Place an additional comma here in order to correctly set off your list) and jumble sales take much of my time, it was (Keep your writing in the past tense here.) still a pleasant, challenging and meaningful experience for me. During this time, I found that the ability of cooperation, (spelling correction) organization, (Again, place an additional comma here in order to correctly set off your list) and communication, which will play important roles in my future profession, had (Again, keep your writing in the past tense here.) been improved.
When my father was transferred (Use of the passive voice is the convention here.) to Zhengzhou, the capital city of Henan province, I continued my middle school study in Zhengzhou. Although at the point of transfer I was a little homesick, I overcame my feeling and quickly adapted to the new environment.
After my enrollment (spelling correction) into one of the best high schools in Henan province, knowledge related to business sparked my interest to know more and deeper about the (The article "the" is necessary here.) business world. I followed the news and media and listened to the opinions of economics about the Wall Street (Proper nouns are always capitalized.) crisis. I was curious to know what went wrong with the financial system and the long, hard task of fixing it, (An additional comma here correctly sets off your final phrase.) and how everybody could be unconsciously influenced.
As I am seriously considering specializing in business administration after keenly interested in acquiring more theoretical knowledge and practical skills in this field, I would like to be given the opportunity to learn a great deal from the staff at EUR. (Omit the word "university" here, as it's already included in the initials EUR.) Its accreditations and rankings, (An additional commas is required here.) as well as its renown as one of top business schools in Europe definitely draw my attention. I believe that the EUR can provide me with a world class programme, which can be a great start of my business career.
Moreover, I am fascinated about the multinational study environment that Erasmus University Rotterdam (spelling correction) offers to an international student such as myself. (This is a slight rewording of your sentence for the sake of clarity.) I feel very excited when I meet new people and make new friends, (Additional comma required here.) especially with those who have different backgrounds, cultures, (Additional comma required here.) and habits from me. Since the Netherlands has been an international and open country, and international students are all welcome at the EUR, I believe there are lots of chances to get in touch with people I may not have an opportunity to meet in my usual life. It will broaden my horizons and help me to deal with cultural diversity, which could come in handy if I would like to work for international companies.
Last but not least, I am convinced that language skills will gain much credit for individuals. Multinational firms with business on a global scale are more inclined to hire people with bilingual or multilingual ability. Studying in the Netherlands will not only improve my English speaking, but also offer me a chance to learn Dutch, which can contribute a lot to foreigners to adapt to local culture.
To sum up, I have determination and positive motivators to reach higher levels of performance. Being a successful business administrator is the motivation of my study and part of my self-actualization. I hope that EUR can offer me the chance to help me make my dream come true (spelling correction).
Thank you very much for considering my application. I am looking forward to your positive response. It would be a valuable opportunity to study at EUR.
Sincerely, (the more usual closing)