Export/import issue/question

Hi,

I'm trying to move a database from postgresql 7.4 to postgresql 8.1.
Unfortunately this is not going well. This is what I did:

pg_dump --file dbsnapshot --format=t -a -b

and then I installed 8.1, and attempted the following:

pg_restore --file dbsnapshot --format=t --table=ingeststatus -a

But, I get the following error:

pg_restore: [tar archiver] could not find header for file toc.dat in tar
archive

However, a tar tf shows that toc.dat is indeed in the dbsnapshot file:

kwright(at)baetis:/common$ tar tf dbsnapshot
toc.dat
2.dat
3.dat
4.dat
5.dat
6.dat
7.dat
8.dat
9.dat
10.dat
11.dat
12.dat
13.dat
14.dat
15.dat
...

The tar is pretty large:

-rw-r--r-- 1 root root 6892524032 Jun 19 09:48 dbsnapshot

Any idea what I'm doing wrong?

Karl