to start a workflow on an SpListItem you will need to write the following code ;
SPListItem currentItem = //Your Item To start the workflow on it;
currentItem.Web.AllowUnsafeUpdates = true;
SPWorkflowManager wfManager = currentItem.Web.Site.WorkflowManager;
SPWorkflowAssociationCollection wfAssociation=
currentItem.ParentList.WorkflowAssociations;
foreach (SPWorkflowAssociation Association in wfAssociation)
{
if (Association.Name == "WorkflowName")
{
wfManager.StartWorkflow(currentItem, Association,Association.AssociationData);
break;
}
}
Try it , but notice that you cant start a workflow from another workflow , you must postback to start the workflow , you can make a form with a button to start the workflow ...