I have had The Extrex Legend and the earlier 60CSX work well with nRoute. It was not till I purchased a second 60CSX when they were clearing them out that i discovered a COM issue with the second new 60CSX. Aftermuch discusssion with Garmin they acknowledged that the new GPS with SW ver. 2.40m had an incompatibility with nRoute. Through research on the internet I discovered SW ver. 2.40m meant a new Mediatek chipset. The older 60CSX with SW ver. 3.00s worked fine. This was the SIRF III chipset. In all discussions with Garmin they never achnowledged they changed the chipset. The lengthy discussion with Garmin ended with them exchanging my new 60CSX SW ver. 2.40m with a like new unit they had in their Support Centre. It was a 60CSX with SW ver. 3.00s. They said it was the last one they had. They also said that all overhaul exchange units you will get back from them wil have the SW ver. 2.40m (Mediatek chipset). The one they sent back to me works great with nRoute.
Although I have never tried it other have told me a Comm problems can sometimes be fixed with nRoute by:
-Reinstalling the garmin USB drivers
- Using a free program called GPSGate.

Good luck with your use of nRoute. I thing it is a great program no mater how old it is.