I have a CSV or text file of positions I would like to import into WL to backtest. I am running into trouble when trying to use System.Data; or System.Data.OleDb;. Is there some other way I can do this? Thanks

I have a car. I want to get to another state by a road (maybe to the north or perhaps to the south). I'm running into trouble with the police officer. Is there some other way I can get there?

We're support technicians but no mind readers. You have some list of positions (what are they?) in a file whose contents and formatting you're not showing. The code that you've written for that task is a mystery. Furthermore, you don't even show the error message that occurs when accessing two totally unrelated .NET namespaces which deal with databases (but not text files). To sum things up, you're not giving any details to help you.

Back to your question. As this question (of importing historical trades) is being raised several times each year, searching the forum (recommended to any user: new or seasoned) would undoubtedly find some existing topics like these:

How to post my own purchase and sales points? (the most useful for a newbie)

Upload and trade 110 different tickers easily
Importing Buy/Sell Signals
Backtest Based on Equity Screens
Trading Signals: execute AtLimit/AtStop signals at exact price?

And more. Also, there's a new, related solution that had not been discussed before:

Import historical trades from Quicken reports (QuickenFile)