The problem is most likely related to your connection string. You can check for that by trying to connect to the database
SqlConnection conn = new SqlConnection(connString);
conn.open();
conn.close();
If the above code throws an exception then indeed it is your connection string. You can try to fix it yourself or have a look at this article for more information.
http://msdn.microsoft.com/en-us/library/ms254947.aspx[
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However if you are able to connect to the database, then the problem lies within the
workflowRuntime object. If you post more details on the exception that you are getting I am sure some one will be able to help you further.
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