Can you post screenshots of the maintenance plan with the settings, and also the query for your manual backup via the script button at the top of the GUI

Are you backing up to the same location for both the tests?

Toast

You will need to find the tasks which cannot be upgraded, eg ActiveX tasks etc and re-code them for 2012

Will require upgrading to 2005/2008 then to 2012

http://blogs.msdn.com/b/mattm/archive/2012/05/04/migrating-sql-server-2000-ssis-packages-to-sql-server-2012.aspx

OK, going to need screen shots of services.msc with the general properties of the services in question then as something isn't right.

Is there a reason for using sp_OA methods instead of sp_send_dbmail?

sp_OA utilities memory from outside of the allocated server RAM, so if you have a heavily memory constrained system, sp_OA...

Sounds like permission errors.

Post the error messages you are getting please.

Just out of interest if you run

SQLServerManager11.msc

from RUN can you see the 2012 instance?

Reggae Reggae Sauce

There's nothing in the KB articles that 4042 contains the 4033 fixes so I am going to say both.

Is there any reason your not considering SP3 10.50.6000

What is stored on the LUN you are removing? If the system DBs are on that LUN then yes they will need moving too. If the SQL Binaries...

Are you sure both instances are 2012 or below? One isn't 2014/2016 CTP?

Ok, this is starting to make a bit more sense now the more I lookup OpCentre. It has its own database engine and its own T-SQL dialect which is...

http://blogs.msdn.com/b/sqlprogrammability/archive/2006/03/29/564110.aspx

Maybe this will explain the behaviour