I don't use ISPConfig to manage my nameservers (they're handled by the VPS provider), but I have configured nameservers via ISPConfig before. I'm pretty sure that your DNS setup needs revision, though.
ISPConfig's DNS interface is a little confusing in one particular area: A records should include only the subdomain name (use an empty string if there is no subdomain for the record).
If I'm not mistaken, you should have a wildcard record somewhere in there (no value in the name field):
Type Name Data
A mail 188.8.131.52
A www 184.108.40.206
I'm not sure about NX, PTR, and NS records... maybe one of the other folks who uses bind with ISPC can comment.
Or, you could spend $5 on the manual