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Palm synchronization is, to some degree, broken in Mac OS X 10.5 and later. To install the appropriate iSync Palm Conduit, which is bundled in your configuration, you need to launch iSync and choose the Enable Palm OS Syncing… option. This will install the conduit, defeat presently active conflicting Palm conduits, and allow you to configure it.
If you receive an error that the HotSync Manager is not properly installed, that is a completely UNRELATED issue, and must be resolved by invoking a change to Palm—not Apple—permissions, using a procedure I can describe to you. Please start another thread if you need to know how to do that, as it has nothing at all to do with this issue.
Even if you elect to do and choose to use iSync and the iSync Palm Conduit, you will still face issues regarding calendar synchronization. You should instead investigate the
Missing Sync for Palm OS, which resolves all Mac OS X 10.5 or later issues with Palm synchronization, except for a specific one involving iCal 3 calendars. Resolution of that issue requires a yet-unreleased update to iCal.
Again, if you should choose to pursue the opportunity involving the Missing Sync for Palm OS, please start another thread if you have questions about that.