You have a typo in your connection string property. In the string below you have
nitial Catalog, but it should be
Initial Catalog. Also, as Richard C Bishop said, remove the single quotes from inside your connectionString value.
<connectionstrings>
<add name="EM_DataConnectionString" connectionstring="Data Source='localhost;User ID='user';Password='pwd';<b>nitial Catalog</b>='EM_Data'">
providerName="System.Data.SqlClient" />
</add></connectionstrings>
Try this one...
<connectionstrings>
<add name="EM_DataConnectionString" connectionstring="Data Source=localhost;User ID=user;Password=pwd;Initial Catalog=EM_Data">
providerName="System.Data.SqlClient" />
</add></connectionstrings>