I've encountered a simialr bug today on a new install 6.0 rc1 without demo data:

Environment Information : 
System : Darwin-10.5.0-i386-64bit
OS Name : posix
Your System is not lsb compliant
Operating System Release : 10.5.0
Operating System Version : Darwin Kernel Version 10.5.0: Fri Nov  5 23:20:39 PDT 2010; root:xnu-1504.9.17~1/RELEASE_I386
Operating System Architecture : 64bit
Operating System Locale : en_GB.UTF8
Python Version : 2.7.1
OpenERP-Client Version : 6.0.0-rc1-1
Last revision No. & ID :1718 <email address hidden>
Traceback (most recent call last):
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/netsvc.py", line 489, in dispatch
    result = ExportService.getService(service_name).dispatch(method, auth, params)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/service/web_services.py", line 598, in dispatch
    res = fn(db, uid, *params)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/osv/osv.py", line 122, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/osv/osv.py", line 176, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/osv/osv.py", line 167, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/addons/base/module/wizard/base_module_upgrade.py", line 100, in upgrade_module
    _, pool = pooler.restart_pool(cr.dbname, update_module=True)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/pooler.py", line 60, in restart_pool
    return get_db_and_pool(db_name, force_demo, status, update_module=update_module)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/pooler.py", line 39, in get_db_and_pool
    addons.load_modules(db, force_demo, status, update_module)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/addons/__init__.py", line 869, in load_modules
    r = load_module_graph(cr, graph, status, report=report)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/addons/__init__.py", line 715, in load_module_graph
    init_module_objects(cr, package.name, modules)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/addons/__init__.py", line 409, in init_module_objects
    result = obj._auto_init(cr, {'module': module_name})
  File "/opt/local/src/openerp/addons/magentoerpconnect6/sale.py", line 259, in _auto_init
    cr.execute("ALTER TABLE account_invoice_line ALTER COLUMN discount TYPE numeric(16,6);")
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/sql_db.py", line 76, in wrapper
    return f(self, *args, **kwargs)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/openerp-server/sql_db.py", line 129, in execute
    res = self._obj.execute(query, params)
NotSupportedError: cannot alter type of a column used by a view or rule
DETAIL:  rule _RETURN on view report_account_invoice_product depends on column "discount"

Is this the same bug, or should I make a new report?