Navigon on SD card: No go?

[drbanks]

Two apps that I've really looked forward to moving to the SD card are Garmin Navigon and Audible. Both have significant "other" storage requirements; in the case of Navigon, it's maps that aren't shared with the Here infrastructure, and in the case of Audible, it's the actual audio books.

Audible seems to work fine off the SD card. Navigon is another story. When I moved it over and tried to run it, it gives me some sort of cryptic "can't connect" error. When I move it back to the Phone storage, it's fine.

Is this just me?