Salvage Kit Error
The bug is as follows:
Consume a salvage kit until it has only 1 salvage remaining.
Double-click the salvage kit in order to active the salvage option.
Then, as fast as you can, click an item you want to salvage, and immediatley double-click the salvage kit again (as if you intend on using the salvage kit again). In order to be quick enough, place the salvage kit and the item next to each other.
This will produce the error "Guild Wars cannot complete the operation, please try again later" (error 10).
Speed is what causes the bug, as the status of the salvage takes a second or so to update.
This happens to me quite a lot, because I salvage lots of hydra claws into scales, so I preform the clicks as quickly as possible.
(forgive me if this has been posted, I cannot preform searches..)