That's definitely odd, but I'm not surprised. I've had multiple issues with the Eclipse Indigo 64-bit distribution on Windows 7 and have had to go back down to using 32-bit JDK and Eclipse distributions for now.
Quite honestly I don't think the 64-bit versions of anything are quite fully baked yet.
But I haven't tried DTP with 64-bit bits yet... Sorry.
I have the same problem on Windows 7. I tried with both 32 and 64 bit helios and 32 bit Juno. Posted a separate thread to report this with the title 'DSE has add new connection options greyed out'. But haven't got any response yet.