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I'm not familiar with LiMP, but I just had a quick look over (what I assume is) their website.
It seems they use the Windows boot loader to launch LiMP by modifying the boot.ini file. Unfortunately for you Windows 98 doesn't use boot.ini
You could probably get it working by using GRUB or LILO if you're prepared to 'hack' it in. But that's probably beyond the scope of what a forum can do.
I'd suggest you contact the project maintainer and ask for their advice. They seem reasonably open to email;
Of course you could just take the plunge and replace Windows 98 with Linux