I'm having the same problem with my DeLorme GPS. Initially thought it was a DeLorme issue but now discover it's a Groundspeak one. As for using the method in the response above, I'm aware of that and normally use GSAK rather than the SEND TO GPS for large lists. For singles in a hurry, SEND TO GPS works better. Now it doesn't unless I change my default browser.
As has been said before, Groundspeak, please fix the problem.
Thanks.