Error Code 105-3102. That's apparently what some Japanese users have been running into when trying to access Nintendo's e-shop on their Wii U. Not just the e-shop, but as prolific youtube video poster MEGUMIbernadette (who previously posted a video on the long load times of the Wii U) demonstrates in her video, attempting to update the Wii U firmware results in the same error.
According to Nintendo, the problem is apparently caused by a program inside the Wii U which will need to be patched. This is a bit of a problem for Nintendo (to put it lightly) as they just started beta testing for the Wii U version of Dragon Quest X Online yesterday and the error in question prevents access by not letting users download the beta. One of the perks of picking up the more expensive premium edition of the Wii U was that it included an exclusive registration form for the beta test, so to run into this error kind of puts wrench in the gears for all involved.
Nintendo is currently investigating the error in question and has addressed it on their support page. According to Nintendo, the error has also been confirmed when using Wii Points to purchase a voucher for the Wii U version of Dragon Quest X Online. A patch is scheduled to be released by this weekend.
Launch stumbles are something of a norm in the gaming industry. While this error is a fairly serious issue for Nintendo, the silver lining is that this is the beta test and not the official launch. Hopefully they'll be able to fix the problem in due haste, or as MEGUMIbernadette says in her video, "Our Iwacchi (a cutesy nickname for Nintendo president, Satoru Iwata) will fix it for us!" Please do, Mr. Iwata. Directly.