RedHat Enterprise AS 2.1 with Kernel 2.4'.
I don't know AS2.1 but the 2.4 kernel is considered ancient history around here.
The only fedora with the 2.4 kernel was Fedora Core 1 (2003). That doesn't
mean it's compatible with another system using the 2.4 kernel. Also you may
have issues installing FC1 on newer hardware.
If you are familiar with one of the virtualizations (qemu/virt-manager, virtiual box,
VMWare free client) then you can probably install FC1 as a guest and try it (this
reduced that hardware issues). Otherwise FC1 is probably your best hope among
A better idea is to go to the Centos website and load their 2.x version.
You may need to use their yum repo to upgrade to 2.1.
In case you are unaware, RH releases the sources for their enterprise products, but you have to pay to get the binaries (both legal wrt GPL). Centos removes a few RH icons and rebuilds the binaries, and distributes freely.
I wouldn't use Centos on a production server (no support and it undercuts RH biz) but it's a great way to test against a RH clone - almost identical.
Here are some AS2.1 docs.