1) Parameter Incorrect message. This is a known problem with Windows 9x with 2.40. It doesn't happen on NT/2000/XP. We'll be fixing this shortly in an upcoming 2.40.1 patch release.
2) Wall-o-red. You're right on this one. 2.40 added logic to show the destination graph - even if it was timing out. You're the first person to notice that there's no way to turn it off through the User Interface, though! Thanks for bringing this to our attention.
There is a workaround for this one - you'll just have to edit the .INI file.
Get the IP address of the destination you're tracing to, but don't want to graph (if Ping Plotter is running, it will be listed on your wall-o-red graph).
Close all instances of Ping Plotter.
Using notepad or your favorite text editor, open the "PingPlotter.ini" file from your Ping Plotter directory. Look for a section named: [VisibleTimelineGraphList]
In that section, add a line for the IP Address above, like this:
207.46.249.222=0
Substitute your own IP address for the one above, but do have the "=0" at the end.
Save the file and close your editor.
Restart Ping Plotter and trace to the destination. No wall-o-red.
We'll get this fixed so there is a right-click menu on the time graph to hide it - although we'll have to think a bit about how to *show* it again if that's wanted (maybe a right-click on the Destination Address Unreachable line to show-hide the time graph).
Thanks for the report!