Fetch mails with DavMail and IMAP account

[sebastianl]

Hi,
I'm trying to run the otrs.PostMasterMailbox.pl file in the command line (perl otrs.PostMasterMailbox.pl) and it's throwing the following errors:

Traceback (2916):
Module: Kernel::System::MailAccount::IMAP::_Fetch (v1.12) Line: 127
Module: Kernel::System::MailAccount::IMAP::Fetch (v1.12) Line: 79
Module: Kernel::System::MailAccount::MailAccountFetch (v1.17) Line: 424
Module: main::Fetch (v1.4) Line: 180
Module: otrs.PostMasterMailbox.pl (v1.4) Line: 93

I opened the mentioned files and check the functions but it's not clear how to fix this issue.

Which files do I have to change to get this working?
Because also from the OTRS Admin interface I get these errors (ADMIN > PostMaster Mail Accounts > Fetch mail ) Could you please help me on solving this? Thanks in advance.