I'm trying to implement CI for the company I work for, and having troubles with the Migration Tool. I got a package.xml with all the metadata information from my origin org, and I'm trying to deploy it to a new, completely clean org. However, I'm getting a lot of errors (like 667 errors!) while deploying to the clean org. Some of them include:
 

[sf:deploy] 19.  objects/Trabalho__c.object (Trabalho__c.SBF_Contecnica1_Trabalho) -- Error: This View Unique Name already exists or has been previously used.  Please choose a different name. (line 1027, column 16)
[sf:deploy] 72.  reports/Financeiro_Plenos_ADM/Emprestimos.report -- Error: filterlanguage: Invalid value specified: 64.
[sf:deploy] 115.  reports/Plenos_ADM_e_ENG/Encargos_Sociais.report -- Error: filterlanguage: Invalid value specified: 64.
[sf:deploy] 238.  workflows/Apontamento__c.workflow (Apontamento__c.SE_Envio_do_email_do_RDA) -- Error: In field: recipient - no User named name@company found (line 48, column 13)
[sf:deploy] 336.  classes/Teste_Trabalho_AtualizaSugestaoCrea.cls -- Error: Dependent class is invalid and needs recompilation:
    build   28-Apr-2015 16:44:16
[sf:deploy]       Teste_Cria_Objetos: line 7, column 55: Invalid field cnpj__c for SObject Account (line 5, column 5)
[sf:deploy] 414.  profiles/SolutionManager.profile -- Warning: You can't edit tab settings for SocialPersona, as it's not a valid tab.
[sf:deploy] 443.  email/unfiled$public/Informacoes_do_Diario_clonado.email -- Error: Apex class 'doDisplayController' does not exist

What I find odd about this is that some errors, like the 443 (the last one above), tell that a class does not exist, while the same class is specified in the package.xml in the retrieve and deploy methods.

Has anyone ever experienced something like this before? What can I do to successfully copy a whole Salesforce org?

PS:

I have access to the sandbox, and other clean orgs. I don't have access to the original org.