I am running Win XP server, and when I try to start sever on HLDS for NS, I get this error host_error:
couldnt get DLL API from \nsp\addons/metamod/dlls/metamod.dll!

p.s. I have the NS metamod.dll

Your path is messed up. I don't think you can have both forwards and backwards slashes in it.

Check your liblist.gam file in the NSP folder. It should show:

gamedll "addons\metamod\dlls\metamod.dll"

Hmm, My slashes were the other way in my dedicated server/nsp. I did that but now the error just says
couldnt get DLL API from \nsp\addons\metamod\dlls\metamod.dll!

any help?

What have you edited so far? Just the liblist.gam? Have you verified the target path and try recopying the metamod.dll to that folder?

Does your liblist entry look like mine?

It is acting rather oddly now. HLDS loads fine, but when I click start server, it says loading, then dissapears and nothing happens.

You are using a modified shortcut to launch the server yes? It sounds like you are just trying to run steam...

?? I am just clicking on the HLDS button in games window.

any help?

Try lauching the server via a shortcut to get a better idea of where it is dying.

ie:
c:\SteamDir\hlds.exe -console -game nsp +maxplayers 20 +map ns_eclipse

I did that but its still the same. If you dont know, my prob is that i click on HLDS, then it says preparing to play DS. Then i fill in the info and click Start Server. It says starting server... then it dissapears and does nothing.

If you are 'filling things in' then you are not lauching from the shortcut properly. Your first step is to stop launching the server from inside steam itself. Once you have done that then diagnosing other errors becomes much easier. You should also temporality disable any meta or amx mod plugins. If your server has remote access PM me and I'll take a look at it.