Surround your processing with code that changes the CurrentUICulture. Since BackgroundWorker uses a thread pool, I would recommend using a try/finally to leave things the way you found them.
In DoWork:
Code Snippet
System.Globalization.
CultureInfo oldCulture =
System.Threading.Thread.CurrentThread.CurrentUICulture;
try
{
System.Threading.
Thread.CurrentThread.CurrentUICulture =
new System.Globalization.CultureInfo("en-US");
// Your processing here.
}
finally
{
System.Threading.
Thread.CurrentThread.CurrentUICulture = oldCulture;
}