SQLite Error: Cannot delete WhereListIterator`1: it has no PK

I'm trying to delete records from a database using SQLite/C# in Visual Studio 2012. Whenever I attempt to delete a record I get the following error:

SQLite Error: Cannot delete WhereListIterator`1: it has no PK

I am wanting to delete records using two different methods. Either delete using only the EID, which is the primary key, or delete records where the user provides everything but the EID.

if (EID_TextBox.Text != String.Empty) {
    if (Roster_Enrollment.Any(x => x.EID.Equals(Int32.Parse(EID_TextBox.Text)))) {
        App.DBConnection.Delete(Roster_Enrollment.Where(x => x.EID.Equals(Int32.Parse(EID_TextBox.Text))));
        Message_TextBlock.Text = "Enrollment deleted.";
    } else
        Message_TextBlock.Text = "Enrollment not found.";
}
else if (Roster_Enrollment.Any(x => x.CourseNo.Equals(CourseNo_TextBox.Text) && x.SectionNo.Equals(SectionNo_TextBox.Text) && x.Tno.Equals(Tno_TextBox.Text)))
    App.DBConnection.Delete(Roster_Enrollment.Where(x => x.CourseNo.Equals(CourseNo_TextBox.Text) && x.SectionNo.Equals(SectionNo_TextBox.Text) && x.Tno.Equals(Tno_TextBox.Text)));
else
    Message_TextBlock.Text = "Enrollment not found.";