The Aperture plugin hasn't been updated in some time, and it is using
outdated contacts retrieval code... at this time I don't have a new
version planned. iPhoto2Gmail is still under active development and a
new version will be out this weekend.
In the past, connectivity issues like this one were usually due to
proxy settings or poorly behaving DNS. Are you by any chance behind a
proxy or using a third party DNS server?
JI