Licensing for MS SQL Server 2000 & MSDE 2000

Hi,

I'd like to ask about the licensing requirement for Microsoft SQL Server Service Manager v8.00.20.39 and Microsoft SQL Server 2000 Desktop Engine (MSDE 2000).

Let me describe the situation.

In the company I'm working for, we have an accounting software using MS SQL Server Service Manager v8.00.20.39 and MS SQL Server 2000 Desktop Engine (MSDE 2000).
You can see MS SQL Server Service Manager v8.00.20.39 running in the systray and you can see a folder at this path: C:\Program Files\Microsoft SQL Server (where I found a readme file stating MS SQL Server 2000 Desktop Engine (MSDE 2000)).
We have 2 servers like this: 1 Windows Server 2003 R2 Enterprise and 1 Windows Server 2008 R2 Standard.

The company paid the license for the accounting software but no license has been paid for MS SQL. MS SQL is only installed because of this accounting software and it was the supplier who did the installation.

So my simple question is: do you need to purchase a license for this version of MS SQL?

I couldn't find the answer on Microsoft websites because everything related to licensing redirects you to the latest version of MS SQL Server (2012) which is not what I'm looking for.

Thanks in advance for your help.