ODP.NET

I've been searching for a solution to this problem but I still can't figure out what's wrong. I hope someone can help.

I created a class project (built it into a .DLL), then I referenced that DLL in my Web application. Basically the DLL has a function which connects to my local Oracle XE database, and uses a connection string which is defined in the web.config. The function looks like this:

public partial class Oracle
{
public string ServerConnected()
{
OracleConnection myConnection = new OracleConnection(ConfigurationManager.AppSettings["ConnectionStringOXE"]);
myConnection.Open();

return myConnection.ServerVersion;

}
}

I know my connection string ("Data Source=server:1521/XE;User ID=hr;Password=hr;") works fine, because I tried connecting using Visual Studio 2005 and it worked. But whenever I call the above function above from an aspx script, I always get an ORA-24315 error when the Open() command is executed. But if I copy paste the above code and put it directly in my aspx script, I don't get an error.

I wonder if there's additional settings required to connect to the database from function compiled into a .DLL

I hope someone can provide an answer. Thanks in advanced!