Can't install PE 4.0 on PB G4 w. OS 10.8.9

Whenever I try to install my Photoshop Elements v. 4.0 on my 12 inch
Mac Powerbook G4 running Mac OS 10.4.9, I get the error message
"There were errors installing the software. Please try installing
again." I get this message when installing with or without Safe Boot,
and from either the PE4 CD or from the desktop. Logging out and then in
doesn't help.

FWIW, my old PE v 2.0 installs effortlessly from the CD with normal (not
Safe) boot. Any suggestions anyone? Thanks.

Mel Comisarow