My Navigon File is in the extSDcard.
I just moved the folder from the internal to ExtSDcard and Navigon works fine.
PS Nearly all my GPS programs ( Sygic -TomTom etc ) are in the ExtSDcard
Samsung Galaxy S III GT-I9305
Latest custom CM 10.1
Motorola Xoom WiFi+3G (MZ601)
ROM: Latest CM10.1 Nighty with Stock Kernel