Upgrade SQL Server 2000 engine
How to get the 8.00.194 (!!!!!!) server to 8.00.2040:

You can download Service Pack 4 (8.00.2039) from here, which you will need to install before you can install the 8.00.2040 hotfix.

How to restore a 2000 .bak to a 2008 server:

You may need to clarify your actual requirements and clean up the question, but if you are trying to ultimately restore a SQL Server 2000 .bak file from server 2 to a SQL Server 2008 instance somewhere else, there is no reason to restore to server 1 first - just restore the .bak directly on the SQL Server 2008 instance (regardless of the source, 8.00.194 or 8.00.2040).

How to resolve the invalid tape format message:

You may have an invalid RESTORE statement, or you may have a corrupt backup. If the former, add the RESTORE statement to the question. If the latter, take a new backup (there are some tedious workarounds if you are restoring to 2005 or higher, but they include potentially allowing data loss). I don't believe this error message will be resolved simply by upgrading server 1. If @@VERSION were the issue (and it can be in some cases), you'd get a different error message than one about tape format.