What exactly is in the log when you are experiencing issues? Don't forget that for the time being, till the proxy harvester gets added, it is very important that proxies be used for searching to prevent your IP from getting limited by Yahoo. If you are seeing lots of log entries of searching and 0 new targets being found this is more than likely the issue.
If this is not what is happening in your case please
read this and reply here with the information requested so that I may help you further.