OK, I'm getting the same error, and have tried to find out more, but I'm no C++ programmer!
Situation: attempting to connect to a pop3 server via Opiemail, after a long pause response is 'unable to initialize folder'
Diagnostic action: an opiemail from a Konsole. Attepmeted the connection, an reverted to the Konsole to watch for messages. After a long pause (again!), opiemail printed 'FEHLERNUMMER 5' to the console. I know enough German to recognise 'Error Number'!
Went looking in the source. This is where my lack of C++ knowledge may show! The FEHLERNUMMER message appears to arise from the function pop3_mailstorage_init() in
noncore/net/mail/libmailwrapper/pop3wrapper.cpp. The number 5 comes from the response to a call to mailstorage_connect(). I may well be missing something, but grepping through the Opie source for the definition of that function hasn't turned anythig up.
However, it would seem that Error 5 is being thrown by a POP3 connection routine - so what could error 5 be in POP3 terms? According to the Microsoft knowledgebase (yeah, yeah, but it was the first one to come up on Google!), POP3 errors all start "0x800CCC9" - the one with a 5 on the end is 'No messages on server'.
Fine, so this long pause followed by 'unable to initialse folder' probably actually means ' no messages available.'. Two things remain:
1. Why such a long pause, during whcih opiemail actaully appears to have locked up? Surely it doesn't take that long for a POP server to respond - my desktop machines show a 'no messaages' response within seond or two.
2. Improved & more informative handling of a POP3 return code which isn't really an error would be a Good Thing.
I'm filing a bug report....