I"m not familiar with NOD32, but I do have some experience with A2 antii-dialer, so bear with me while I do some thinking 'out loud' here that might help you solve the problem.
1) A2 anti-dialer will detect legitimate dialers - it says so in its program description. In my opinion, its live detection is not specific enough. For example, I have three dial-up connection short cuts on my desktop. A2 anti-dialer live detection detects each one of them as Windows Explorer attempting to dial out. If I tell the program to 'always allow.' My concern is that it then won't detect true bad ones that also utilize Windows Explorer.
2) A2 anti-dialer is still quite new. Frankly, I consider it more as a beta program, even though it is not labeled as such. NOD32 might
be picking up part of its detection database and flagging it as an infection - this would be a false positive.
3) Question: Is your A2 anti-malware the free version or the payware version? If the latter, the anti-dialer protection is part of it and you don't need the separate anti-dialer program.
4) I"d avoid the Beta updates unless you want to test them. Beta means that they are still working out problems, and the end-user is finding what those problems are. It is possible that what NOD32 is detecting is one of the Beta updates to the Anti-dialer program.
Hope this helps,