I "THINK" I figured out the 404 error!

[Bondman007]

Ok, so I had DDO installed from back in the day when I pre-ordered it. Nothing had changed and everything was running fine until I was absent for a bit and an update hit. (My DDO game was also under a slightly different folder path than what is defaulted). I uninstalled the game (doing the complete method as described in turbine support knowledge base) then redownloaded the game and reinstalled it to the default directory this time and...tada, running the game IN ENGLISH!

I believe this error may have come from one of two sources (or perhaps both):
#1) I had DDO installed to a non-default directory on my CPU possibly causing the 404
or
#2) because I hadn't technically uninstalled the launcher, the older launcher may not have been searching the server at the right place for the required update files. (this essentially would be a DDO side error)

I hope this helps anyone else having this problem. But ultimately, a 404 is NOT necessarily an error with not being able to connect (therefore having nothing to do with isp and/or firewalls), instead it is generally an error from the server itself stating that it can't find a particular file or path. (Check wiki-pedia 404 errors for clairification). Anyways, thanks to everyone that tried to help. Ultimately, looks like a full reinstall may be needed to clear this problem UNLESS there is a way to perhaps just update the launcher itself? Be worth checking into to save a 2 hour D-load. See ya in game.

[Aldured]

Well after plowing through most of this thread : http://forums.ddo.com/showthread.php?t=134315 Tech supports FAQ and what not heres what happened and what I did:

First I attempted to use the backup folder, got 201 errors.
Tried reinstalling, got 201 errors.
Since this might indicate corrupt files I redid the steps described above a couple of times
Eventually found the log and saw that some DLL didnt work so I upgraded another computer and copied its directory files, same
Redid the backup dir, same
Toyed around with permissions, nothing
Uninstalled, Created a new user account and installed there, nothing.
Copied all files from the computer I upgraded and replaced my own. And now I jumped into the 404 error (which would no longer go away reinstall or not).
After repeating many permutations of the above I unistalled, deleted remaining files and reinstalled in another directory.
Then I MANAGED TO LOG IN but windows firewall kicked in to my surprise (as I never actually activated it, using win 7 and seems it just came activated prefab so careful guys). But this isn't too much of an issue just add an exception.

So guys I hope at least one of all those solutions I just mentioned works out for you. I had a huge advantage tho, I have a USB external HDD (from a dearly missed laptop that was more powerful than my current, snif) so I always keep a backup copy of the DDO installer just in case.

Happy questing !!!