IBM OmniFind should do the trick, It indexes your files and then you can search the index very quickly. It also does caching of documents and other nifty stuff. It is based on Apache Lucene and there is a free (as in beer) version, IBM OmniFind Yahoo Edition. The free version will work with up to 500 000 documents. I used it for searching a number of networked drives with circa 50 000 files on them which it did very well.

It's all because of foolish requirements in the fifth and sixth section of the "Lag om ansvar för elektroniska anslagstavlor " , approximately translated, The Electronic bulletin board responsibility act.

Which states that the provider is responsible for the comments if they obviously contains either illegal content (hate speech, child pornography, calls for riots) or
  illegally republished copyrighted content (i.e a very blatant copyright violation).

And even if you didn't have the time to check all the comments or if you missed something, you are responsible, since you have been negligent ( sixth section).

However even if he had been covered by the Freedom of the Press part of the Swedish constitution he would have been under investigation anyway, since hate speech is exempt.

He will probably receive a small fine and that's the end of it.