The MSExchange team blog has announced what effectively amounts to a recall of the initial Update Rollup 3 for Exchange 2007 SP3.  Apparently there was a risk of database corruption with the initial version which they say has now been fixed with the newly updated version of the same Update Rollup.

If you were one of the first adopters of Update Rollup 3, you should read what they have to say on how to address the issue.

You can find the details at their blog:

http://blogs.technet.com/b/exchange/archive/2011/03/31/announcing-the-re-release-of-exchange-2007-service-pack-3-update-rollup-3-v2.aspx

For those of you experiencing MAPI logon errors with location 5, we've updated our technical bulletin to address all known causes of the issue.  If your incident hasn't been resolved yet, consult this new version of the document here:

http://support.diditbetter.com/kb/a2e_216.aspx

Does Add2Exchange work with the iPhone and Android-based phones? Absolutely! We work on the Exchange server to deliver your appointments, contacts and tasks to the folders which your phone sees. From there, any phone capable of Exchange sync can see them.

From the summary:

If the directory used by the system to store MAPI dynamic profile information is unavailable for any reason, the synchronization service will not be able to log on.  However, the console and logon test are able to successfully log on.  The solution is to restore access to the profile directory or change the profile directory location via a registry key.

You can find this bulletin at:

http://support.diditbetter.com/kb/a2e_218.aspx