Excel OpenText method

Answer 1

From the KB article you linked to:

One caveat is that if you pass multiple parameters, they need to be passed in reverse-order.

From MSDN, the parameters to OpenText are:

expression.OpenText(Filename, Origin, StartRow, DataType, 
TextQualifier, ConsecutiveDelimiter, Tab, Semicolon, Comma, 
Space, Other, OtherChar, FieldInfo, TextVisualLayout, DecimalSeparator, 
ThousandsSeparator, TrailingMinusNumbers, Local)

So if param1 holds your filename then you are currently trying to pass that as the Local parameter and you aren't passing anything to the Filename parameter which is required