"Interface not registered" has nothing to do with the host of the data files.
It means that a Decal DLL/object is not correctly registered in your system.
If the update is your only Decal problem, you can download the current files to your Decal directory from our Meginjarder server.
Ensure that Decal is closed, then rightclick every link and "Save As" to "C:\Program Files\Decal" or any path you used when installing Decal :
http://mj.lastdynasty.net/memlocs.xml
http://mj.lastdynasty.net/messages.xml
http://mj.lastdynasty.net/decalplugins.xml
http://mj.lastdynasty.net/updatelist.xml
If you prefer a totally fresh re-installation, you have to get rid of ANYTHING reminding Windows of Decal (= Registry entries).
I suggest the following :
1) uninstall Decal from Control Panel->Add/Remove Programs
2) start the Registry Editor (Start->Run->regedit<enter>)
3) on the left side expand/climb down to "HKEY_LOCAL_MACHINE", "SOFTWARE". Look for "Decal".
If not found, go to step 3c)
3a) if you do not care about currently installed plugins, simply delete the whole "Decal" key by pressing Del. That means you have to reinstall the plugins later too.
3b) if you want to keep the plugins, delete every subkey of "Decal", BUT NOT "Plugins". Later you only have to reinstall SpellFilter and ImpFilter.
3c) close REGEDIT
4) use the Windows Explorer to check whether the folder "C:\Program Files\Decal" (or the path you entered when installing Decal) is empty. If not, delete every file it contains.
5) although not really necessary, I suggest to reboot now to ensure that any Decal-related DLL is wiped from memory.
6) reinstall Decal. Depending on 3) either only install SpellFilter+ImpFilter or your complete plugin list.
Upon starting the first time Decal will mourn that it cannot find its XMLs and it should upload them similar to pressing the Update button.