I find it to depend on many things, mostly what base you use.
For extracting the DBC I use this at the moment:
Code:
MPQEditor.exe /merged "C:\Games\World of Warcraft\Data\misc.MPQ" "C:\Games\World of Warcraft\Data\enGB\locale-enGB.MPQ" /patch "C:\Games\World of Warcraft\Data\wow-update-base-16016.MPQ" "C:\Games\World of Warcraft\Data\enGB\wow-update-enGB-16016.MPQ" "C:\Games\World of Warcraft\Data\enGB\wow-update-enGB-16048.MPQ" "C:\Games\World of Warcraft\Data\wow-update-base-16048.MPQ" "C:\Games\World of Warcraft\Data\wow-update-base-16057.MPQ" "C:\Games\World of Warcraft\Data\enGB\wow-update-enGB-16057.MPQ" "C:\Games\World of Warcraft\Data\enGB\wow-update-enGB-16309.MPQ" "C:\Games\World of Warcraft\Data\wow-update-base-16309.MPQ" "C:\Games\World of Warcraft\Data\enGB\wow-update-enGB-16357.MPQ" "C:\Games\World of Warcraft\Data\wow-update-base-16357.MPQ" "C:\Games\World of Warcraft\Data\wow-update-base-16516.MPQ" "C:\Games\World of Warcraft\Data\enGB\wow-update-enGB-16516.MPQ" "C:\Games\World of Warcraft\Data\wow-update-base-16650.MPQ" "C:\Games\World of Warcraft\Data\enGB\wow-update-enGB-16650.MPQ"
Using version 3.5.0.740 - some builds ago there was an issue with the patcher function, it got fixed later on. Check that you don't use an older version than mine.