I am not sure with this, can you try to fire the workflow manually from code like this
static void Main(string[] args)
{
{
using(SPWeb web = site.OpenWeb())
{
SPList l = web.Lists["Shared Documents"];
//SPWorkflowAssociation associationTemplate = l.WorkflowAssociations[0];
SPWorkflowAssociation associationTemplate = l.WorkflowAssociations.GetAssociationByName("Approval", System.Globalization.CultureInfo.CurrentCulture);
foreach (SPListItem lt in l.Items)
{
site.WorkflowManager.StartWorkflow(lt, associationTemplate, associationTemplate.AssociationData);
}
};
};
Console.WriteLine("Done...");
Console.ReadKey();
}