As far as we can tell, the file Vog.dll is mostly (only?) used with the game "MTA SA" , Multi Theft Auto.
All information points to vog.dll being a re-named "OGG.DLL".
Identify this file by MD5 Checksum 0602f672ba595716e64ec4040e6de376
Vog.dll is often found in sub folder \MTA\mta\;
X:\Games\GTA San_Andreas\MTA\mta\
X:\GTASA\mta\
Available for free download at dll-files.com ogg.dll page