Hi
As said, the File Locks are probably files in the process of OCR with Tesserect OCR - and “scanning” a 20 page PDF can take a while longer than a reading a textfile…
However, not even a textfile is correctly indexed… 
I quite agree that a working search is essential for such a system. Using local search is NOT an alternative, as a lot of users only have the web obtion on the road…