Actually, a 90000 error is purely client-side. It literally means your client severed its connection to the server for any number of reasons: legitimate loss of connection, a bad, or malformed packet received by the client, etc. That really does suck you lost the potash. I lost mats crafting yesterday as well... but it was just a raptor leather synth so... ya

The only real solution to this problem is when SE fixes the client netcode bugs, and deals with the ever-growing ISP packet throttling issues.