Ok using the 5.0 BETA 3 migration wizard I am in the same situation still. It is migrating the folders but no email, calender items, or contacts.
In the log it has now added the following lines at the beginning which leads me to suspect that something about the LDAP setup isn't correct.
Mail entries in the log are now showing the subject like the following:
16-11-2007 09:19:16 : ldap_result returned no LDAP_RES_SEARCH_ENTRY. Success, 101
16-11-2007 09:19:16 : ldap_result returned no LDAP_RES_SEARCH_ENTRY. Parameter Error, -1
Also this was probably in the logs before and I just didn't see it but here is another type of error I am seeing.
16-11-2007 09:22:08 : (MI): WARNING: Message skipped, Failed to get Mail Interface Sub([RBG7-L] - Re: Page Style), d(Sat, 2 Jun 2007 07:34:29 -0000), fid(269)
It appears that it is enumerating everything correctly but is just unable to read the actual contents of the GW email boxes.
16-11-2007 09:26:27 : (MI): WARNING: Message skipped, Failed to get Appointment Interface d(Z) fid(76217240)