I recently had this problem in a Merlin Legend I installed. Two things were causing the problem:
1. I had to remove * from the disallow list, thought I am not sure how it got there.
2. PacBell was "dropping" the first digit dialed after the feature code. For example *82 555-1212 was being received as *82 551-121 by PacBell. Dialing *82 X555-1212 where X was a random digit was odd but it resulted in the call being completed properly. There is a setting for "second dial tone delay" or something similar which I had to increase to correct this problem. If this is the source of your problem, email me and I will find the instructions on how to increase this setting for you.