I have never gotten a Sqlite error. So I agree with Ephialtes on that issue.
Now on the fact of what the cahe.db file does. Well, this kind fella dredges up what it does in the most simplest of terms.
The cache.db is a cache where are the files you download from other servers are stored.
Would saying I am on a Mac change anything?
Now correct me if I am wrong, but aren't Sqlite errors only on Macs? At least, that's where I've only seen them.