Inside of a Script Task in SSIS, I need to make a call to an SQL database. I have a connection string that was created when I added the database to the data sources folder,
You must check the privider of the connection that your are trying to instantiate.
You can't cast a OleDb.OleDbConnection connection as a SQLClient.SQLConnection, the parameters are different.
OleDb.OleDbConnection
SQLClient.SQLConnection