This error will normally occur when your internet connection was disrupted while patching. This may or may not be true but from what I've experienced this is the normal cause for Runtime Error.
THE FIX :
1. Locate the place where you store Dragon Nest.
2. Scroll down until you see Patch00000086.tmp (v.86 is the current DN SEA version.)
Note : As you can see the file is called tmp meaning ''Temporary file'' meaning it's the patch file and it will be there just until the file finished downloading.
3. Now if you noticed there's a file size besides the filename itself. It depends on your internet speed. Let's take an example of a 300kbps download speed. If you have opened DN and encountered the Error 2 times, the file size will most probably be 600-1200 kbs. What actually is happening is that you are still patching the game even though the error appears. The launcher will stay there for around 1-2 seconds so you will have time to patch the game for 1-2 seconds.
4. Now keep clicking and receiving the error until the Patch00000086.tmp file disappear. Now a new error will appear ( I've forgotten to screen the error so yeah.) It will say something like ''Could not verify Patch Version''. A 2nd error will appear afterwards saying something like ''Launcher has encountered a problem please reinstall game client''. DO NOT REINSTALL
Note : The amount of time you will click and receive the error TOTALLY depends on your internet speed connection.
5. After the file Patch00000086.tmp disappear you may or may not receive the fake error in step 4 again. If you did the steps correctly, you will able to play DN normally. Hope this helps and goodluck!
Edited by RawrXLR, 06 February 2013 - 03:15 PM.