[Hostile_Badger]

I'm new to source scripting and trying to create a mini plugin that does a command on round end.

Line that's creating errors:
HookEvent("teamplay_round_win",event);

also the code file is uploaded as well

[nosoop]

Your event function needs to have one of these exact return types and arguments, since that's what HookEvent expects.

void event(Event ev, const char[] name, bool dontBroadcast) {
    // ...
}

[Sreaper]

Although already answered above, here is corrected version of your code.
You also don't need to include public for the event callback either. Only SM and third party plugin forwards need to have public.

PHP Code:

public void OnPluginStart()
{
    HookEvent("teamplay_round_win", SomeNameHere);
}

void SomeNameHere(Handle event, char[] name, bool dontBroadcast)
{    
    PrintToServer("Admins Reloaded");
    ServerCommand("sm_reloadadmins");
} 


[Hostile_Badger]

Thanks for the help you two, I couldn't find the documentation for that anywhere on the wiki or even youtube.

I'll be using that API directory that noscoop sent alot more.

[Marttt]

Events (SourceMod Scripting) - Post Hooks