ODP.NET :: Exception Occurring When Connecting To 11g Database Using 10g ODAC

We've got a 32 bit .Net windows application which uses ODAC 10g (1.x) to connect to a 10g database on the backend. Things work fine in this deployment.

We're in the process of setting up a new development machine. This machine has ORACLE 11g (64 bit) installed on it. We're running into issues connecting the the database.

This is the code block we're using to connect to the database:
=======================================
string dataString = "user id=xxx;password="xxx";data source=localhost:1521/ORCL";
using (OracleConnection oraconn = new OracleConnection(dataConn))
{
oraconn.Open();
Oracle.DataAccess.Client.OracleCommand cmd = new OracleCommand(sOraSQL, oraconn);
[code]........

We get an exception on the "oraconn.Open()" command.

The output window in VS2010 shows this:
-----------------------------------------------------------
A first chance exception of type 'Oracle.DataAccess.Client.OracleException' occurred in Oracle.DataAccess.dll

The oraconn variable looks like:
-------------------------------------------
- oraconn {Oracle.DataAccess.Client.OracleConnection} Oracle.DataAccess.Client.OracleConnection
+ base {Oracle.DataAccess.Client.OracleConnection} System.ComponentModel.Component {Oracle.DataAccess.Client.OracleConnection}
ConnectionString "user id=xxxxx;password="xxxxxx";data source=localhost:1521/ORCL" string
ConnectionTimeout 15 int
DataSource "localhost:1521/ORCL" string
[code]........

The details of the exception are:
---------------------------------------------
- ex {""} System.Exception {Oracle.DataAccess.Client.OracleException}
+ [Oracle.DataAccess.Client.OracleException] {""} Oracle.DataAccess.Client.OracleException
+ Data {System.Collections.ListDictionaryInternal} System.Collections.IDictionary {System.Collections.ListDictionaryInternal}
HelpLink null string
[code].........

To reiterate, in our original deployment (10g database with 10g (1.x) ODAC, we can connect fine with the database. It's with the new setup (11g database with 10g(1.x) ODAC) that we are having issues. We've previously been able to deploy on client machines which were using ORACLE 11g. To accomplish this, we had to make sure that the password was inclosed in quotes (").

What is going on here? What should we be looking at? How do we go about debugging fixing this?