Thanks for writing in - sorry you're having trouble.
If you've already got an older version of MultiPing installed, uninstalling that version first may
help get you around this issue.
There is a way to uninstall older versions while still keeping all of your saved settings/license information intact as well. If you go to your control panel and select "Uninstall a program," find MultiPing from the list of available programs, right click on it, and select "Change." Once the setup wizard pops up, you'll have options to "repair" or "remove. If you click on the "remove" option - you'll then be brought to a screen where you'll have the options to "remove all MultiPing settings, directories and log files," and "remove MultiPing license key." You can uncheck both of these boxes to keep all of your configuration settings and license information intact - and then try installing the newer version.
If this doesn't seem to help things up and running, we've also got an article that provides a few alternate strategies that may help out. Have a look here:http://www.pingman.com/kb/92
There are also instructions in the above article on how to create an install log. If none of the other points in the article help to get things working, would you be able to create an install log and send that over to us (via email at email@example.com)? We'll be more than happy to take a look at that and see if we can help get to the bottom of this issue.
Please let us know where this leaves you!