You wrote :
*** This bug is a duplicate of bug 982751 ***
    https://bugs.launchpad.net/bugs/982751
** This bug has been marked a duplicate of bug 982751
   6.1 - Installing the Document Management module breaks leads

I disagree with the reason for duplicate status, because : I DID NOT INSTALL DOCUMENT MANAGEMENT MODULE !

Please find below the list of modules and extras installed :
crm	 Customer Relationship Management	 CRM	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
project	 Project Management	 Project Management	 Easy	 OpenERP SA	 6.1.1.1	 6.1.1.1	 Installed		
account_accountant	 Accounting & Finance	 Accounting and Finance	 Normal	 OpenERP SA	 6.1.1.1	 6.1.1.1	 Installed		
hr	 Human Resources	 Employee Directory	 Easy	 OpenERP SA	 6.1.1.1	 6.1.1.1	 Installed		
sale	 Sales Management	 Sales Management	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
hr_timesheet_sheet	 Human Resources	 Timesheets Validation	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
stock	 Warehouse Management	 Warehouse Management	 Easy	 OpenERP SA	 6.1.1.1	 6.1.1.1	 Installed		
purchase	 Purchase Management	 Purchase Management	 Easy	 OpenERP SA	 6.1.1.1	 6.1.1.1	 Installed		
project_gtd	 Project Management	 Todo Lists	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
project_issue	 Project Management	 Issues Tracker	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
hr_recruitment	 Human Resources	 Recruitment Process	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
hr_holidays	 Human Resources	 Leaves Management	 Easy	 OpenERP SA	 6.1.1.5	 6.1.1.5	 Installed		
hr_expense	 Human Resources	 Expenses Management	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
hr_payroll	 Human Resources	 Payroll	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
account	 Accounting & Finance	 eInvoicing	 Easy	 OpenERP SA	 6.1.1.1	 6.1.1.1	 Installed		
account_analytic_analysis	Sales Management	Contracts Management	Normal	Camptocamp 6.1.1.1	 6.1.1.1	Installed		
account_analytic_default	 Accounting & Finance	 Account Analytic Defaults	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
account_analytic_plans	 Accounting & Finance	 Multiple Analytic Plans	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
account_budget	 Accounting & Finance	 Budgets Management	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
analytic_journal_billing_rate	 Sales Management	 Billing Rates on Contracts Normal OpenERP SA 6.1.1.0	 6.1.1.0	 Installed		
analytic_user_function	 Sales Management	 Jobs on Contracts	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
base_action_rule	 Sales Management	 Automated Action Rules	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
base_contact Customer Relationship Management Contacts Management	 Expert	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
edi	 Extra Tools	 Electronic Data Interchange (EDI)	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
email_template	 Marketing	 E-Mail Templates	 Expert	 OpenERP,OpenLabs	 6.1.1.1	 6.1.1.1	 Installed		
fetchmail	 Extra Tools	 Email Gateway	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
hr_attendance	 Human Resources	 Attendances	 Easy	 OpenERP SA	 6.1.1.1	 6.1.1.1	 Installed		
hr_contract	 Human Resources	 Employee Contracts	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
hr_payroll_account	 Human Resources	 Payroll Accounting	 Expert	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
hr_timesheet	 Human Resources	 Timesheets	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
hr_timesheet_invoice	 Sales Management	 Invoice on Timesheets	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
l10n_fr	 Account Charts	 France - Accounting	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
mrp_jit	 Manufacturing	 Just In Time Scheduling	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
pad	 Project Management	 Collaborative Pads	 Easy	 OpenERP SA	 6.1.2.0	 6.1.2.0	 Installed		
pad_project	 Project Management	 Specifications on PADs	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
product	 Sales Management	 Products & Pricelists	 Normal	 OpenERP SA	 6.1.1.1	 6.1.1.1	 Installed		
project_messages	 Project Management	 In-Project Messaging System	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
project_mrp	 Project Management	 Create Tasks on SO	 Easy	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
project_scrum	 Project Management	 Methodology: SCRUM	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
project_timesheet	 Project Management	 Bill Time on Tasks	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
survey	 Extra Tools	 Survey	 Normal	 OpenERP SA	 6.1.1.0	 6.1.1.0	 Installed		
web_process	 Uncategorized	 Process	 Normal		 6.1.2.0	 6.1.2.0	 Installed

As stated in comment earlier on, the error message disapears after "location_id" and "contact_id" fields are created in the crm_lead table.

Regards