Здравствуйте, уважаемый Ochkarik еще раз хочу Вас поблагодарить, Вы совершили невозможное - нашли в Интернете Platform SDK старше Августа 2002 года!
Простите, забыл кавычки - надо было так: (Win 98, 98SE DDK) "ОТКАЗЫВАЮТСЯ РАБОТАТЬ" с Visual C++ 6.0 (!), и требуют для работы 
Visual C++ 5.0.
Цитата:
The Essential Guide to the 
Windows 98 DDK ((98)DDKGUIDE.DOC) и Installing the Windows 98 DDK (W98GS.CHM)
"VC++ 6.0 
Do not use. This version has name decoration 
INCOMPATIBILITY problems in some cases, making it unsuitable for building VxDs. 
Do not use with the Windows 
95 DDK or with the 
Windows 98 DDK.
Note that Visual C++ 6.0 is NOT SUPPORTED for any of the samples."
VC++ 5.0 The 
HIGHEST RECOMMENDED VERSION to compile sample code found in the Windows 98 DDK. General driver and VxD development.     
If you are using Visual C++ 5.0, some warnings may occur unless you have installed Visual Studio 5.0 
Service Pack 3. 
However, once you start building your own driver, you might 
NEED header files from the 
Platform SDK that are not on this release of the Windows 98 DDK. You can either 
copy the required header file or files from the Platform SDK to the appropriate Include directory under either %98DDK% or %VCPPDEV%, 
or you can install the Platform SDK and edit the Setenv.bat file in %98DDK%\BIN to run the Setenv.bat file that is installed in %MSTOOLS%. 
Цитата:
Microsoft 
Platform Software Development Kit (SDK), August 2001 Edition ((PSDK 08 2001)contents.htm)
System Requirements 
Operating System Requirements 
Windows® XP
Windows XP 64-Bit Edition 
Windows XP Professional 
Windows XP Home Edition 
Windows® .NET Server (Beta 2) 
Windows® 2000 Server 
Windows 2000 Professional 
Windows NT® 4.0 Server 
Windows NT 4.0 Professional 
Software Requirements
Microsoft Windows NT 4.0 Service Pack 6 or later 
Microsoft Internet Explorer 5 or later 
Microsoft Windows Installer version 1.2 runtime executables on Windows NT version 4.0, and a native version of Microsoft Windows Installer on other platforms. 
A C/C++ compiler (Microsoft® 
Visual C++® 6.0 or later) to build C/C++ samples.
A prerelease C/C++ compilation system is provided to target Windows 2000 64-Bit Edition (prerelease). To gain access to the compilation system, during setup you must select Win64 Development Components (prerelease). 
Microsoft® Visual Basic® to build Visual Basic samples. 
Hardware
Approximately 1150 MB of disk space is required for a full installation, but a good deal more space is needed to compile all the samples. Significantly more space is needed when installing to a FAT partition. However, you may reduce disk space usage by choosing the Custom install option and selecting only the components you need. 
--------------------------------------------------------------------------------
Microsoft Platform SDK, June 2001 Edition (((PSDK 06 2001)contents.htm))
System Requirements 
...
A C/C++ compiler (
Microsoft Visual C++® 6.0 or later) to build C/C++ samples. 
...
Windows 9x/ME Installation
Installation of the Platform SDK and its component SDKs on Windows 95, Windows 98, and Windows ME is no longer supported. You can still build applications for these target operating systems from the PSDK Build Environment; 
you just can't develop ON them.
Tested Compilers 
The Platform SDK has been tested with 
Visual C++® 6.0 Service Pack 4. Some samples 
may not build without applying Visual Studio Service Pack 4. See 
http://msdn.microsoft.com/vstudio/ for more information about Visual Studio service packs. Samples can be built with other compilers, but other compilers were not completely tested. 
If you are using Visual C++ 5.0, it is RECOMMENDED that you upgrade to 
Visual C++ 6.0. The import libraries included with this release of the Platform SDK have a 
DIFFERENT FORMAT than that used by Visual C++ 5.0, which improves performance and decreases storage requirements. 
Building COM Samples on Windows 98 on Windows ME 
The COM samples located in %MSSDK%\Samples\COM  SHOULD NOT BE BUILT on Windows 98 or Windows ME, though they can be built on Windows XP RC1 32-bit (Home Edition or Professional), Windows 2000 (Professional or Server), or Windows NT 4.0 (Professional or Server) to target Windows 98 or Windows ME (except for Com\Fundamentals\DCom\TimeOuts\PingResp). 
--------------------------------------------------------------------------------
Т.е. для:
Windows 98 DDK  July 1998 (1998-07)  и   
Windows 98 SE DDK  May 1999 (1999-05) нужен 
Visual C++ 5.0.
а для:
Microsoft Platform 
SDK June 2001 (2001-06)
и
Microsoft Platform 
SDK August 2001  5.1.2601.0  (2001-08)
нужен 
Visual C++ 6.0.
Для разработки драйверов под Win9x
последний совместимый Platform SDK с полной поддержкой Visual C++ 5.0 это:
Microsoft 
Platform SDK September 1999  (
1999-09)
Last Platform SDK to fully support Visual C++ 5.0 (1997-04-28).
Буду ОЧЕНЬ ПРИЗНАТЕЛЕН, если дадите живую ссылку.
P.S.
вот последние версии Windows 95 DDK выходили и позже июля 1998 (но требовали Visual C++ 4.0 и Microsoft Win32 Software Development Kit): 
You can find handy printable documentation on the 
July 1998 and later versions of the 
Windows 95 DDK CD-ROM, located in the 
\NEW95DOC path.  Note that this path is NOT automatically copied to your hard disk when you install the DDK; you need to copy the files manually.  
(кстати было бы неплохо, если кто-то выложит все содержимое этой папки 
\NEW95DOC и вообще самую последнюю версию Windows95 DDK).
С уважением, 
Bruno Mann.