Inner Cursor Error

Hello,

I have been using dynamic sql in an inner cursor and I get an error about the fetched variable of the outer cursor. How can I fix it?

	DECLARE A1 CURSOR GLOBAL FOR
		SELECT  Iid, Server, Dbname 
		FROM	@OuterTable;
	OPEN A1;
	FETCH NEXT FROM A1 INTO @aId, @aServer, @aDbname;
	WHILE @@fetch_status <> -1
	BEGIN
		SET @SQLCursor = 'DECLARE D1 CURSOR GLOBAL FOR 
		SELECT Id, StatusId, Server, DbName FROM [' + @aServer + '].['+@aDbname+'].dbo.Rooms;';
		EXEC sp_executesql @SQLCursor;
		OPEN D1;
		FETCH NEXT FROM D1 INTO @dId, @dStatusId, @dServer, @dDbname;
		WHILE @@fetch_status <> -1
		BEGIN
			SET @SQL='SELECT @aId, @dId, @dStatusId, d.DateCreated, d.DocumentSize, dah.ActivityId, dah.DocDeleted 
			FROM [' + @dServer + '].['+@dDbname+'].dbo.Documents d 
			INNER JOIN DocumentActivityHistory dah ON d.Id = dah.DocumentId;';

			INSERT INTO @DocActivity
			EXEC sp_executesql @SQL; --, '@aId nvarchar(50) output',@aId output;
			FETCH NEXT FROM D1 INTO @dId, @dStatusId, @dServer, @dDbname;
		END
		CLOSE D1;
		DEALLOCATE D1;
		FETCH NEXT FROM A1 INTO @aId, @aServer, @aDbname;
	END	
	CLOSE A1;
	DEALLOCATE A1;

And the error is;

Thanks,