Databases :: Using An Oracle Database Causing Exception

I'm a little confused as to what is causing the following error is a very simple application: System.ArgumentException: An OLE DB Provider was not specified in the ConnectionString. An example would be, 'Provider=SQLOLEDB The code-behind has this:

OleDbConnection conn = new
OleDbConnection(ConfigurationManager.ConnectionStrings["db_conn_qa"].ConnectionString);

In the Web.Config, the following is present (note the Provider is clearly there):

<configuration>
<appSettings/>
<connectionStrings>
<add name="db_conn_qa" connectionString="Data Source=xx;Persist Security Info=True;User ID=xx;Password=xx;Unicode=True"
providerName="System.Data.OracleClient" />
</connectionStrings>
<system.web>
...