We have a webpart to search documents that is not searching the sub-site of the site where the search webpart is placed
Any suggestion on why the webpart does not give results of the documents located on a subsite.
Have you configured your search based on Scope ? If not try create one on site collection or central admin. Add a new rule which includes a link to the subsite and check how many items it shows. Remember to include the items.
WHat is the depth selected in the content source, make sure that the content source setting is set to crawl everything under the given URL.