Hi Guys ! I am very happy to find this very interesting thread because i mis isync from the beginning of use my N900.
I try to install this plug-in and in the application folder i can't find "isync.app" !!
After having a look on the log files i saw the following infos :

Apr 8 19:17:40 samourai installd[564]: PackageKit: ----- Begin install -----
Apr 8 19:17:40 samourai installd[564]: PackageKit: request=PKInstallRequest <1 packages, destination=/>
Apr 8 19:17:40 samourai installd[564]: PackageKit: packages=(\n "PKJaguarPackage <file://localhost/Volumes/N900iSyncPlugin/N900iSyncPlugin.pkg>"\n)
Apr 8 19:17:40 samourai installd[564]: PackageKit: Extracting /Volumes/N900iSyncPlugin/N900iSyncPlugin.pkg/Contents/Archive.pax.gz (destination=/var/folders/zz/zzzivhrRnAmviuee+++++++++++/-Tmp-/PKInstallSandbox-tmp/Root, uid=0)
Apr 8 19:17:41 samourai installd[564]: PackageKit: Shoving /var/folders/zz/zzzivhrRnAmviuee+++++++++++/-Tmp-/PKInstallSandbox-tmp/Root (1 items) to /
Apr 8 19:17:41 samourai installd[564]: Error -43 getting LS info for file://localhost/Applications/iSync.app
Apr 8 19:17:41 samourai installd[564]: Installed "the phone plug-in" ()
Apr 8 19:17:41 samourai installd[564]: PackageKit: ----- End install -----
Apr 8 19:17:42 samourai Installer[553]: Removing temporary directory "/var/folders/He/HerRJNAWGgKD-LFE0yd8aE+++TI/-Tmp-//Install.553440d9s"
Apr 8 19:17:42 samourai Installer[553]: Finalize disk "Macintosh HD"
Apr 8 19:17:42 samourai Installer[553]: Notifying system of updated components
Apr 8 19:17:43 samourai Installer[553]:
Apr 8 19:17:43 samourai Installer[553]: **** Summary Information ****
Apr 8 19:17:43 samourai Installer[553]: Operation Elapsed time
Apr 8 19:17:43 samourai Installer[553]: -----------------------------
Apr 8 19:17:43 samourai Installer[553]: zero 0.01 seconds
Apr 8 19:17:43 samourai Installer[553]: disk 0.01 seconds
Apr 8 19:17:43 samourai Installer[553]: install 2.11 seconds
Apr 8 19:17:43 samourai Installer[553]: -total- 2.13 seconds
Apr 8 19:17:43 samourai Installer[553]:
Apr 8 19:17:43 samourai Installer[553]: IFDInstallController 321830 state = 5
Apr 8 19:17:43 samourai Installer[553]: Displaying 'Install Succeeded' UI.

The install process never give any error ! this error (Error -43) only appear in the install.log file.

if somebody can help me that would be very appreciated.
Thanks in advance and sorry for my bad english !

Which OS X do you use?

Mac OSX 10.6.3 (snow leopard)

Thanks for your reply.

hmpf?! I have the same OS here and it works fine (even on my 10.5 system).

did you checked manually if there is an iSync icon in your application directory?

There is'nd any iSync, not in the application folder and not else !!

looks like you have to reinstall it from your OSX discs.

I reinstall it 3 or 4 times and always i have the same error message and always i never can find any trace of the iSync application on my complete disc and system !!

hmm that sounds strange... maybe you should go to an apple related forum and ask there why iSync always disappears.

I will try this, yes !
Thanks you for help

I'm stupid !!
I uninstall isync on my Mac and i want to start the application !!! yes ! it's possible to be so stupid :-) (i need to stop smoking !)
After correct re-installing, the plug in works great ...
Thank you assetburned and other for help and develop this very useful plug-in :-)