IMetaDataImport::FindTypeRef fails to return TypeRef token for known Type from a reference assembly

I am writing and IL re-writing profiler for .NET assemblies.

I have the following code snippet and applying it to the EntityFramework.dll assembly function.

//Enumerate all reference assemblies for current assembly				
hResult = pMDAImport->EnumAssemblyRefs( &assemblyEnum, assemblyRefs, numElements( assemblyRefs ), &assemblyRefsCount );
// Walk through all referenced assemblies to find System.Data.IDbCommand token
//
for( unsigned assemblyRefIdx = 0; (unmatchedTypes > 0) && (assemblyRefIdx < assemblyRefsCount); assemblyRefIdx++ )
{
assemblyRef	= assemblyRefs[ assemblyRefIdx ];
WCHAR tempAssName[50];
ULONG szAssNameRet = 0;
hResult = pMDAImport->GetAssemblyRefProps(assemblyRef, NULL, 0, tempAssName, numElements(tempAssName), &szAssNameRet, NULL, NULL, 0, NULL);
if (hResult == S_OK)
{
 if( CLogger::isLevelEnabled( LL_Debug ) ) CLogger::Log( LL_Debug, "Searching for dependent types in assemblyRef(%08X) (%d/%d) - %S\n", assemblyRef, assemblyRefIdx + 1, assemblyRefsCount,  tempAssName);
}
hResult = m_pMDImport->FindTypeRef( assemblyRef, L"System.Data.IDbCommand", &typeRef );

if( (m_idbCommandTypeToken == mdTokenNil) && SUCCEEDED( m_pMDImport->FindTypeRef( assemblyRef, L"System.Data.IDbCommand", &typeRef ) ) )
{
	m_idbCommandTypeToken = typeRef;
}

The logging confirms it sees System.data as one of the referenced assemblies which should contain the TypeRef forSystem.Data.IDbCommand

014.04.22.15.33.50.951  [00002B0C]  DEBUG    Searching for dependent types in assemblyRef(23000003) (3/13) - System.Data

Can you tell me why the FindTypeRef fails and how to get around this ?

Regards

Sanjay

The hResult error is

Sanjay Mehta