[Samba] DNS problems in my domain

[3ddFreak]

The users in our network are experiencing some dns problems. 
When i take closer look to our samba configuration I see that we have a corrupted ldb file (/var/lib/samba/private/sam.ldb.d/DC=DOMAINDNSZONES,DC=********,DC=COM.ldb). 
I can still access the DNS entries from the Microsoft remote server administration tools. 

What are my best options? 
I have a backup of the ldb files from 2 months ago(no dns entries changed since), should i try to replace the ldb file with the older one? Why not? 
Can i safely delete the ldb and will a reboot of samba recreate the file? 
Should I start over? Create a new Domain Controller? 

Can anyone explain the purpose of this file? Is it only responsible for the internal DNS? 

Error in Syslog: 
ldb: ltdb: tdb(/var/lib/samba/private/sam.ldb.d/DC=DOMAINDNSZONES,DC=********,DC=COM.ldb): tdb_rec_read bad magic 0x444e4940 at offset=88929584 

Ubuntu 14.04 LTS 
Samba version: 4.1.6 

Thx in advance