Hi
this is a different question depending what program you have developed
and if it may afdfect other patents/copy rights. My statement was only
that MS does not prohibit selling excel sheets. So you don't have to
pay them a fee (but of couese you're not allowed to ship the Excel
application itself with your file).
For the other questions: This is very dependet on your countries legal
framework. So you may check this with a lawyer
