You can't use a PCI upgrade card in any machine other than the machines listed:
Power Macintosh Series 7300, 7500, 7600, 8500, 8515, 8600, 9500, 9500/180MP, 9515, 9600, 9600/200MP
Workgroup Server 7350, 8550, 9650
Daystar Genesis and Millennium Series
Mactell XB-Pro
Power Computing PowerTower Pro*, PowerWave
UMAX J700, S900
The term "PCI" does not refer to the slot the upgrade goes in, it refers to the line of Macs that used PCI slots ( as opposed to the older nubus slots ).
The PCI upgrade card actually fits in a special "daughter card" processor slot.
It will not function in a Beige G3, Blue and White G3, or any of the G4s.