Simple EventHandler/Provider using a variadic template and function pointers

I'm trying to implement an EventProvider/Handler system to facilitate setting up a small application with reactive GUI for a school project. This particular approach to the broader Observer pattern is not mandated, but it seems like the most robust and lightweight - provided it's actually possible.

#pragma once

#include <vector>;
#include <algorithm>;

/// Provides a lightweight interface for implementing event-based behaviour.
template <class ...arg> class EventProvider
{
public:
    /// Defines a pointer to a function equipped to handle an event from this provider.
    typedef void( *EventHandler )(arg... arguments);

    EventProvider();
    virtual ~EventProvider();

    void Subscribe( EventHandler handler );
    void Unsubscibe( EventHandler handler );

    void Notify( arg... arguments );

protected:
    vector<EventHandler> _handlers;
};

template<class ...arg>
EventProvider<...arg>::EventProvider()
{}

template<class ...arg>
EventProvider<...arg>::~EventProvider()
{}

template<class ...arg>
inline void EventProvider<...arg>::Notify( arg... arguments )
{
    for ( auto handler : _handlers )
    {
        handler( arguments );
    }
}

template<class ...arg>
inline void EventProvider<...arg>::Subscribe( EventHandler handler )
{
    if ( find( _handlers.begin(), _handlers.end(), handler ) == _handlers.end() )
    {
        _handlers.push_back( handler );
    }
}

template<class ...arg>
inline void EventProvider<...arg>::Unsubscibe( EventHandler handler )
{
    _handlers.erase( remove( _handlers.begin(), _handlers.end(), handler ),     _handlers.end() );
}

What I have so far builds fine on its own, but if I actually try and include this header and use the code in other places, I get dozens of errors, all of them duplicates of...

C2238 unexpected token(s) preceding ';'

C2143 syntax error: missing ';' before '<'

C4430 missing type specifier - int assumed. Note: C++ does not support default-int

On the line where I've declared my vector of EventHandlers.

C2509 syntax error: '...'

C3211 'EventProvider<>::FunctionName': explicit specialization is using partial specialization syntax, use template <> instead

On all of the function signatures in the implementation following the class template declaration.