I put this in the folder field in Popper_Configurator: "INBOX,[Gmail]/Entw&APw-rfe,[Gmail]/Gesendet,[Gmail]/Papierkorb" and it works fine. Popper selects and reads from all four folders. Anyway, I put some debug code in Popper 0.20 that lists the folder which it tries to access. This may tell us at which folder it crashes.
Unfortunately I cannot confirm your suggestion. I have these folders in my Gmail account:
Folder: /Entw&APw- rfe" /Papierkorb"
"INBOX"
"Personal"
"Receipts"
"Travel"
"Work"
"[Gmail]"
Nachrichten"
"[Gmail]
"[Gmail]/Gesendet"
"[Gmail]/Markiert"
"[Gmail]
"[Gmail]/Spam"
I put this in the folder field in Popper_ Configurator: "INBOX, [Gmail] /Entw&APw- rfe,[Gmail] /Gesendet, [Gmail] /Papierkorb" and it works fine. Popper selects and reads from all four folders. Anyway, I put some debug code in Popper 0.20 that lists the folder which it tries to access. This may tell us at which folder it crashes.