Using libdvdread for IFO file access from a hard drive in Windows? Is it possible?

[Fullmetal Encoder]

Hopefully someone here can provide me with a little guidance. I'm trying to write a program that will find and strip the timestamps and PES subtitle streams from DVD VOBs as VobSub does and it appeared that libdvdread would be able to help me accomplish this. However, no matter how I compile my test program with libdvdread sources I *always* get:

libdvdread: Encrypted DVD support unavailable.
libdvdnav:DVDOpenFileUDF:UDFFindFile /VIDEO_TS/VIDEO_TS.IFO failed
libdvdnav:DVDOpenFileUDF:UDFFindFile /VIDEO_TS/VIDEO_TS.BUP failed
libdvdread: Can't open file VIDEO_TS.BUP.

The files are unencrypted and on my hard drive. I've tried to track down exactly where in the libdvdread sources it would pull the data from the file for further testing but haven't had any luck. I see many references both in the sources and online to physical DVD in an optical drive but nothing regarding IFO access from a hard drive. Is libdvdread incapable of that? Internet searches dig up info that seems to pertain only to linux usage for direct access off of a DVD disc. Anybody else have any experience using libdvdread in Windows?

I am not an experienced programmer so this may be a noob issue but I just wanted to see if anyone else knew before continuing on a while goose chase to find something that isn't there.

Thanks.