@terence: This is an issue directly related to alz bomb rate... There is a limit to how many alz/items can be dropped on the ground before a player is disconnected. The limit is 4~ alz bombs.
You need to go through dungeons VERY SLOWLY. Kill three monsters at a time, wait until their alz disappear, and then move onto the next three mob. This is the only way you can complete a dungeon right now.
@playah: Undead b2f and b1f are in the same place - just make sure you are using the correct entry item.
Forgotten Temple is at the end of Forgotten Ruins map.