some questions that might help to find a solution:
- how big is the file you have?
- is it being generated on a Unix/Linux system? If yes, do you have any "ulimit" limit set for file size?
- in which filesystem type was this file generated? Some older filesystems have a limit on file size that is somewhat small for today's beasts
- which system is it being analyzed in? in which filesystem? - are you positive you have plenty disk space to hold the dump file? (dumb question, but had to make it to be on the safe side)
- are you positive the file in your computer where you are trying to analyze it is the same size as in the server? (ditto)
- have you transferred this file over FTP? If yes, are you positive you performed a binary transfer, instead of a text one?
Try responding those questions and it's going to be easier to find out what happened.
Cheers