[glow=red]Please refrain from making forum posts about UIS.[/glow]
UPDATED JUNE 2015: If you receive the UIS error, wait 10-15 minutes and try to log on again, it might just be a temporary glitch. You can also try logging into the Playerdex to reset your login information- but again if that doesn't work try again in 10-15 minutes. If you are still suffering UIS after waiting longer than 10-15 minutes ask a staff member for help. The quickest way to find staff outside of the game is in IRC Chat:
http://www.pokemon-world-online.net/chat.php
Any staff member can now release players from this glitch with a simple command. Be patient, we aren't always available, but are always willing to help when we can.
In the past when this error was very common, a lot of the time, the server would not save. If you lose levels or recently obtained Pokemon/badges, this is known as a Roll Back. Nothing can be done about a Roll Back except for retraining/catching the pokes. Even with the Pokemon's ID numbers it is not possible for staff to return them, because basically they never existed. If you log out as soon as the error is discovered, you have a higher chance of not losing much.