That error sounds like your search index got corrupted, you may need to rebuild the search index.
http://www.mojoportal.com/rebuilding-the-search-index.aspx
This kind of thing can be caused if you have 2 IIS web sites pointing to the same folder and you are entering content through both of them, like if you have it running as one site for a localhost and another site for a public site but using the same content and database, then both sites may try to write to the search index at once but there is locking to prevent this and the error indicates the lock timed out.
It can also happen if folder permissions changed on the /Data/Sites/1/index folder, if it can no longer write to the file then it also cannot get a write lock.
Hope it helps,
Joe