error in todiscgui

[Mia1990]

I keep running up on these two errors when i run todiscgui could someone tell me anything about them

libdvdnav:DVDOpenFileUDF:UDFFindFile /VIDEO_TS/VIDEO_TS.IFO failed
and the last error


WARN: Skipping sector, waiting for first VOBU...
STAT: VOBU 0 at 0MB, 1 PGCS

Thank you