HI again
I did play with various ideas offline before- & couldn't find a way to cause the issue with plugins etc; so I'd have to assume something's up with the frameworks I previously mentioned ( b/c webkit brings its own ones in ) yet something that isn't fixed via repair permissions & isn't a problem when run as root....
of course, permissions being 'right' depends on the correct info being available in ( is it the same in Leopard ??) HD/LIbrary/Receipts/ - so make sure the relevant receipts are there ( long shot, but hey! )
'fraid I can't dig up much on the com.apple.Safari.ServiceProvider error.
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I guess if you just want it working, I'd try either running the huge 10.5.3 combo update, or pulling the frameworks via Pacifist from either the combo update of the safari 3.1.1 update ( some info on that
here . On the face of things, your safari app shouldn't be suspect since webkit uses it mostly, but the app can be extracted as per the link too.
In other words.... the non-tech " who cares why? - just fix it! " route is 1: the combo update, 2: reinstall etc