I'm experiencing the same issues with my hero also, my carrier is sprint... i called them and they sent me out another device. once, i got that device activated it started again with the same exact issues. They still do not know why i'm having these issues. But, all i can tell you is that you are not doing anything wrong.

 

Single touch should make the call - but be aware that it somethimes take 5 seconds or so before the next screen comes up showing you are making the call. Can you make a call by going into the contact details and clicking the number there?

 

I tried making a call by single touch and just dialing the number and push talk. either way there is still a lag or delay.

 

I notice it has to do with the signal strength that you have. If you are down to just a couple of bars, it takes a long time to connect. You may notice the same effect on a regular phone.