Robocopy job errorl with "The handle is invalid" on a large (161GB)file

I'm trying to use robocopy to do a restartable-copy (/ZB) of a backup
image from my server to a full-disk encrypted (truecrypt) hard drive.
Whenever robocopy gets to 94.4% of the file though, it starts bombing
out saying that "The handle is invalid." The whole message is...
-----------------------------------------
2008/07/07 14:25:20 ERROR 6 (0x00000006) Copying File \\server\share
\file
The handle is invalid.
Waiting 30 seconds... Retrying...
-----------------------------------------

It just sits there and keeps retrying. If I kill the job and try to
restart it, it starts over from the begining, the /ZB switch isn't
working.

Is there some size limit for robocopy? I could have sworn that I've
copied files larger than this with no problem, but this one just won't
take.

For reference, I'm copying from sbs2003 SP2 to vista SP1.

Sorry - it turns out I was running out of space on the drive. I guess
I could pass the blame on to a bogus error message (why didn't it say
"insufficient space" instead of "handle is invalid"???) but in the end
it's my fault.

I had the same problem and couldn't find the solution anywhere. So I started to add and get rid of flags. When I removed the /b flag (copy in backup operator mode), my backup ran fine. I hope this helps you.