Recently I've Been Using A Secondary Account And Something Odd Keeps Re-Occuring In A Certain Dungeon. I've Gone in Before On My Main Account Monthes Ago And It Worked. The Dungeon Is Den Of Dreams And When I Attempt To Enter The Second Floor The Game Has An Odd Fatal Error Which Other Players Have Gotten Before Under Different Circumstances. The Worst Part Is This Error Makes The Kamaboko Quest Chain Un-Completeable If You Haven't Already Done Said Part. Im Hoping Someone Else May Be Able To Confirm This By Doing The Exact Same Thing As Me. It'd Be Much Appreciated If This Was Fixed So I Can Complete The Sidequest Under My Secondary Account
-MegaManGamer333

1. I assume you meant Cave of Dreams - it works just fine
2. In order to complete the quest; make party with a friend, start the dungeon and just never go to 2nd floor wait for the friend to finish it.
Since Sheryl quest chain is all about simply clearing dungeon, this will work fine.

3. In case even other player's movement to 2nd floor shoots an error, just ask the friend to tell you when he is in the last part.
Only then you join the dungeon by yourself, let him kill the Nurikabe - complete