--- account/account.py	2010-11-26 16:13:59 +0000
+++ account/account.py	2010-12-07 12:56:52 +0000
@@ -631,9 +631,12 @@
         return super(account_journal, self).copy(cr, uid, id, default, context=context)
 
     def write(self, cr, uid, ids, vals, context=None):
+        c_id = None
+        for company in self.browse(cr,uid,ids):
+            c_id = company.company_id.id
         if 'company_id' in vals:
             move_lines = self.pool.get('account.move.line').search(cr, uid, [('journal_id', 'in', ids)])
-            if move_lines:
+            if move_lines and c_id and vals['company_id'] != c_id:
                 raise osv.except_osv(_('Warning !'), _('You cannot modify company of this journal as its related record exist in Entry Lines'))
         return super(account_journal, self).write(cr, uid, ids, vals, context=context)