I remember a problem like this from a long time ago when I played. There are many reasons that you could be getting this error. Do you get a message saying "Update failed. Please restart the game" or something along those lines? If so, try these fixes. They worked back then, don't know if it's the same error now.
1. You might not have enough disk space. Check to make sure you have sufficient space on your computer for the update.
2. Run as admin from the .exe file from the main game folder.
3. This one I'm not too sure about because for me, running as admin fixed the problem. However, there were players who said that onigiri updates through internet explorer & to make sure that internet explorer is updated/online. Credits to Angel Darkfire.
Angel Darkfire wrote:* Onigiri Launcher uses Internet Explorer to do all of its updates (for stupid reasons I can't even try to explain).
* I use Firefox as my Internet browser. As such, I had Internet Explorer uninstalled/disabled.
* Thus, the launcher couldn't connect to the Internet in order to update. (Why, oh why, the stupid thing couldn't just use Firefox is beyond me.)
* To fix the problem I encountered, all I did was reinstall/activate Internet Explorer.
Step by Step Process* Open
Internet Explorer by clicking on the e icon on the bottom taskbar.
* Open
Tools (the circle in the upper right corner below the x or just hit alt+x).
* Select
Internet options from the drop-down menu.
* Click on
Advanced tab.
* Click on the
Reset button.
* Click yes to all the warnings.
* Wait for reset to finish.
* Reinstall Onigiri. <--Might not be necessary. But, I did it as an extra precaution.
* Game screen now opens and lets you register like its supposed to.
Problem fixed.
If none of those work, I'm not too sure :C