Syntax changed in VC++ 7.1?

[MT]

I have a project that uses VC++ 7.0 with a class that implements
ICollection. I have the following methods in the class:
void ICollection::CopyTo(Array * myArr, int index);

IEnumerator * IEnumerable::GetEnumerator();

Boolean ICollection::get_IsSynchronized();

__property Object * ICollection::get_SyncRoot();

int ICollection::get_Count();

I have implemented these methods in a separate C++ file. This all works fine
with VS.NET 2002. When I pulled my project into VS.NET 2003, I get an error
that says:

error C2509: 'get_Count' : member function not declared in
'Namespace::CollectionClass'
error C2509: 'get_SyncRoot' : member function not declared in
'Namespace::CollectionClass'
error C2509: 'get_IsSynchronized' : member function not declared in
'Namespace::CollectionClass'
error C2509: 'GetEnumerator' : member function not declared in
'Namespace::CollectionClass'
error C2509: 'CopyTo' : member function not declared in
'Namespace::CollectionClass'
What am I doing wrong?

MT