Got this neat tip off a fellow on Google+

https://www.onstar.com/web/portal/odm

In the event you try to send an address to your +OnStar equipped vehicle from+Google Maps mobile or web app and find it doesn't work. 
It turns out the Invalid destination name. error you received is a known OnStar bug limitation where destinations sent to your car are saved to your OnStar profile and is limited to 5 addresses. 

To fix go to https://www.onstar.com/web/portal/odm and remove all previously saved addresses.

See also: http://support.google.com/maps/bin/answer.py?hl=en&answer=75505