Save the PowerPoint slide as a .jpeg and then use a different software (such as the ones mentioned in your link) to print as a poster.
In PowerPoint 2007 (or 2010):
Go to the Ribbon Start Menu, click Save As, then Other Formats:

Then in the dialog box that appears, under where you can name the file, there is a drop-down menu for all the formats you can choose from:

Choose .jpeg (or another photo format), name the file, and choose Save. If you have more than one slide, it will ask you:

If you choose Every Slide, it will create a separate .jpeg for every slide and tell you where they are stored, like so:

(the blacked-listed text is the file location).
Then, as I suggested earlier, just open the photo in another program and print on multiple pages.