Data migration from version 7.2.1 to 8.1.5

Hi,

I am trying to write a script which will migrate all the data from a
particular database on version 7.2.1 and restore the same data along
with the full schema on an 8.1.5 database. The database itself will be
created and does not need to be created.

I tried dumping data in tar format using the pg_dump utility (with
version 7.2.1) and restoring it using pg_restore utility (with version
8.1.5). But on running this command:

pg_restore -d mydb -C -u <my_dump_file>

I get the following error:

pg_restore: [archiver] unsupported version (1.10) in file header

Any idea where I am going wrong.

Thanks,
Arindam