I just looked at the log again - you're actually failing to open the Inbox. This puts the problem earlier in the process. We get the entry ID for the Inbox from the Receive Folder table. You'll find this here:
MDB/Display/Receive folder table...
Specifically, we try the entry IPM. I'd try that and see what happens when you click on the IPM entry.
MDB/Display/Receive folder table...
Specifically, we try the entry IPM. I'd try that and see what happens when you click on the IPM entry.