if it is random errors, i only get while playing community matches. they're very rare in worldwide matches.

me neither.
Never got any errors of any sort.

I replaced my router, and now each time I do disconnect at least I get an error number now.  Forgot what it was though, but ya I went from using WEP to WPA2 I believe.  I have now replaced the modem and I'll edit this post once I do another test run.  I am really thinking that modem was the cause and was probably failing from time to time.

EDIT: still getting them 30% or more of the time.  I even shut off my cell phone since it's a smart phone.  Figured it could be giving off interference.  same problem.  so only thing that is left is interference from something else, which I doubt cause everything else works fine  desktop/ps3/xbox/etc.... so it's the 3ds either a program chopping off the connection randomly or the 3ds itself.... geez unreal.

EDIT2: I checked other software and settings.  even cleared cookies and bookmarks out of the lame browser taht comes with the 3ds.  Still desyncs.  So ya, all that is left is playing the 3ds on someone elses network and playing another 3ds on this network to finally conclude it's my 3ds causing problems... I think...

EDIT3: Just got a diff 3ds and still problems.  So now with new modem/router/3ds/wires... running out of things to outrule.  I guess something might be telling the wireless not to work right, or it's the coax cable or the splitter or something unknown to me interfering!