The only time I ever had that issue was when someone had used a pre-order item in their build. If you want to try to get around it, and a much easier way than using the launcher to install lots, is to download
Sims3PackExtractor extract the s3pack lot to package and drop it into your library folder.
I would check the pack with custard first, untick any CC items and re save, because if it contains CC, S3P Extractor wont name your lot package, and you'll just end up with a bunch of extracted numbered files and be unable to tell which is the lot.