Error with muxed mpeg1 files!

I have tried to demux several different mpeg1 files but keep receiving this message:

Skipped -2 zeroes at start of file
mpgtx: AT EOF - please stop me!
mmm, this file does not start with a pack, offset: -2 
use the desperate_mode switch as the first option -X to search for a header in the whole file!
if you want to force the operation. May yield to an endless loop if no valid header is found!
Does not even begin with a 00 00 01 xx sequence!
film.mpg is not a valid mpeg file

What can i do about these muxed mpeg1 files, is there no hope or am i just messing sum shit up. Can someone give a bit of wisdom?

[major]

Are you sure they are mpeg-1 files? Check with the "info" button, or open them in Quicktime player and get info. Try another demuxer like bbDMUX.