I just now downloaded NUpowtG3v103.hqx from within Safari to the desktop of OS 10.4.11. Without opening Classic, I opened Stuffit Expander 5.5 from the Dock and dragged the binhex file onto its window. Voilà! indeed. There was the NUpowr installer beside the binhex in my downloads folder. I'm at a loss to know what is the cause of your difficulty, but it seems neither to lie in the download nor in Expander.

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