Urgent! D type hellenic visa. Can I enter France first

I am a Vietnamese national and have a Greek visa (+1 transit Schengen), D type, single entry, valid from 24/08/09 to 21/11/09, duration of stay 90 days.

Because I have training in Paris from 6 to 11 Sep, so I wanted to fly from Viet Nam to France first with this visa for the training then I will go to Greece later.

But at the check-in at Viet Nam airport, the authority refused to check-in me and cancelled my flight.

Are they correct in refusing my flight for France first?

In case that I should go to Greece first, how can I get a permission to attend the training in Paris from 6 Sep? should I apply for french visa? It is really complex issue when I am a vietnamese nationality which limit my schengen entry permission !!!

Pls help me.
Thank a lot for any reply soon because it is my urgent case!!

Your visa allows you to transit through France to go to Greece, not to attend a training session in France.

If you go first to Greece, you shall need a visa to go to France at the consulate in Athens. If you have a good reason why you wish to travel to France, proof of accomodation, enough ressources, a return ticket to Greece and a travel insurance, there is no reason why your visa would be refused.

You could also apply for it before leaving Vietnam at the French consulate.