Data Adapter FILL Causing Data Corrupt Error In C# Web Service

I hope someone has seen this one...I've got a very simple web method that returns a DataTable from my database. It worked fine until I changed this line of code:

string SqlString = @"SELECT Timestamp, Confession FROM Confessions WHERE ConfessionID = ? ORDER BY Timestamp desc";

To this line of code:

string SqlString = @"SELECT Timestamp, Confession FROM Confessions WHERE ConfessionID = ? AND CategoryID = ? ORDER BY Timestamp desc";


Here is the complete webmethod:

[WebMethod]
public DataTable GetConfession (int ConfessionID, int CategoryID) {

DataTable dt = new DataTable();
dt.TableName = "XMLConfession";

string SqlString = @"SELECT Timestamp, Confession FROM Confessions WHERE ConfessionID = ? AND CategoryID = ? ORDER BY Timestamp desc";

using (OleDbConnection cn = new OleDbConnection (ConnectionString)) {
using (OleDbCommand cmd = new OleDbCommand (SqlString, cn)) {

cmd.CommandType = CommandType.Text;
cmd.Parameters.AddWithValue ("@ConfessionID", ConfessionID);
cmd.Parameters.AddWithValue ("@CategoryID", CategoryID);
cn.Open();

OleDbDataAdapter da = new OleDbDataAdapter (cmd);

da.Fill (dt);
}
}

return dt;
}
To cause the error, all I did was add the AND statement into the query. Now I get this .NET error message every time I try to run this program:


System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt. at System.Data.Common.UnsafeNativeMethods.ICommandWithParameters.SetParameterInfo(IntPtr cParams, IntPtr[] rgParamOrdinals, tagDBPARAMBINDINFO[] rgParamBindInfo) at System.Data.OleDb.OleDbCommand.ApplyParameterBindings(ICommandWithParameters commandWithParameters, tagDBPARAMBINDINFO[] bindInfo) at System.Data.OleDb.OleDbCommand.CreateAccessor() at System.Data.OleDb.OleDbCommand.InitializeCommand(CommandBehavior behavior, Boolean throwifnotsupported) at System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior behavior, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method) at System.Data.OleDb.OleDbCommand.ExecuteReader(CommandBehavior behavior) at System.Data.OleDb.OleDbCommand.System.Data.IDbCommand.ExecuteReader(CommandBehavior behavior) at System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior)

I am using SQL Server Compact Edition 3.5 and C# .NET 2.0. It's worth noting that the web service does this outside of the program as well, so I don't think the problem is in the code that calls it. Also worth noting is that the query itself works fine when I substitute values in and run it in .NET Server Explorer.

Thanks in advance for any assistance.