So as a side note, I'm pretty sure this thread doesn't go in the dev forum.
On to the troubleshooting:
FIRST & MOST IMPORTANT STEP
1. Does you have the same problem if you put your sim in another phone?
if yes, then it is a sim/network problem and you will have to call your carrier.
(DON'T TELL THEM YOU'VE BEEN RUNNING CUSTOM ROM'S! lazy call center
reps will tell you that is why your sim/service isn't working so they don't have to
put any work into fixing your problem)
if no, then continue to step 2.
2. What happens when you try to place a call?
Do you see or hear an error message?
3. What does your phone think the status of its calling abilities are?
does it show signal strength? does it show any unusual icons in the status bar?
4. is the problem location specific?
have you tested the phone at least 7 miles from the location where your first experienced the problem? are other peoples phones on the same service having the same problem as you?