While opening the Tridion UI I am getting this error:
Unable to Initialize TDSE object. Could not load file or assembly 'Tridion.ContentManager.Publishing, Version=6.1.0.996, Culture=neutral, PublicKeyToken=360aac4d3354074b' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515) The type initializer for 'Tridion.ContentManager.TypeRegistry' threw an exception.
Most probably you have some extension or something like this that you have copied from the network and your DLL get locked. You need to find this DLL and click Unblock from the context menu. You will most probably have to do it for all other copied dlls as well. It should look like this: http://www.izenda.com/Site/KB/Uploads/Images/unblock.PNG
In case you have no idea where to look - use procmon
I would also double check Tridion.ContentManager.Publishing dll is in the GAC.
A quick way to see this is to look in c:\windows\assembly and match the version of the DLL as well. You could re-drag and drop the DLL there to make sure all is well.
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