Have a look at your query.
You are inserting 4 Values into 3 Columns.
Also, the command object does not know which connection to use, so you need to append the connection object to the command object. e.g.
command = new OleDbCommand("some command text", connection)
See this article for a step by step;
http://www.codeproject.com/KB/database/simpledbreadwrite.asp[
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