Moved BB from BES 4 to 5, now it wont activate on either. HELP.
 

We are running a super-old version of BES here (4.0.6) with Exchange 2003. As part of upgrade testing, I added BES Express 5.0.1, removed myself from BES 4.0.6 (chose to remove any BB information from mailbox when prompted, wiped the handheld and activated on Express 5. Everything was good.

The tables have turned, and I have been told that we will now be renewing support and going with BES 5.0.2, not express. So, I have to upgrade BES to at least 4.0.7 (or 4.1) to enable Transporter to work (new BES 5 server will be using a new SQL database).
In preparation for that, so I could troubleshoot message delivery, I removed (and chose to remove BB info from mailbox) myself, wiped handheld, and tried re-activating with BES 4.0.6. It doesnt work ... in fact adding my user account into BES shows 'initializing' as the status. I do get a message with ETP.DAT attachment in my inbox. Looking into the logs, I see:

MAPIMailbox::MAPIMailbox(2) - OpenMsgStore (0x8004011d) failed
{0xEA4} MAPI call failed. Error 'The information store could not be opened.', LowLevelError 0, Component 'MAPI 1.0',
{0xEA4} User LastName, FirstName not started

So, I run IEMSTest against my user account, and it can open my mailbox and all tests are completed successfully.
Clearly I can't activate, as the mailbox cant be opened.

Now, I tried wiping again and re-adding myself to the BES Express 5 server, again it doesnt work (just sits there). I checked event logs on the BES Express box, I only see ReloadPagerConfig() failed. I still get a message and ETP.DAT attachment in my inbox.

I have contacted RIM support. So far they are not helpful aside from the obvious (ensure you choose to remove BB info from mailbox when deleting users, etc). Exchange server has not had any changes during this time and is working fine for all other blackberry users (100+ on BES 4.0.6, 1 on BES Express 5.0.1).

Any thoughts. I really dont know what's up.

Update - On the BES Express 5 server, I did a 'reload' for my user account and activation worked.
Still need to figure out why I can't re-activate with the old BES.