Hi Steve
If you need to repair your stl that has errors without going into hours of repairing etc.
There is a service at http://cloud.netfabb.com/index.php that you can upload your stl to and it is automatically repaired , then you download it back fixed. and its free and fast!!!

I have had some real disasters that have come back perfect.

You could also look at backing off on the output resolution as some models will print with no errors at a lower setting.
cheers
shayne