Hmmm... From your description, you haven't really mention a single step of:
[hide]1. Get a copy of the garmin western europe no map from here.
2. Change the extension to .rar or .zip and extract it somewhere.
3. Copy "garmin-nav" file from payload\garmin-nav.app\
4. Paste this to your app directory in your iPhone (i.e. "var\mobile\Applications\[APP DIR]\garmin-nav.app\").
5. Change the owner and permission of the file.
6. Re-run your garmin onboard.[/hide]
I am not sure if you already done the above step due my unclear direction at post #2. Just in case you haven't done it, I suppose try this step first. But if you already done this and the problem persist, I don't think I have another idea other than uninstall your garmin, go to your "var\mobile\Applications\[APP DIR]\" and make sure your garmin folder is gone. Reboot your iPhone and install your garmin again.
Hope this help.