Unable to use the MAPI control in design mode

There is a license fix for your problem on Microsoft's site. Below is the Readme file extracted from the fix:
README.TXT For VBCMPFIX.EXE Utility File

What VBCMPFIX Does
------------------
VBCMPFIX is designed to make sure that the controls and components included with Visual Basic 5.0 are installed properly. VBCMPFIX will detect and fix the install problems for the following editions of Visual Basic 5.0:

Visual Basic 5.0 Enterprise Edition
Visual Basic 5.0 Professional Edition
Visual Basic 5.0 Learning Edition
Visual Basic 5.0 Control Creation Edition

VBCMPFIX does not require any Service Packs installed to use, however upgrading to the latest Service Pack is always recommended. The latest service pack is available at:

http://www.microsoft.com/vstudio/sp

List Of Components VBCMPFIX Will Fix
------------------------------------

Depending upon which edition of Visual Basic 5.0 you have installed, VBCMPFIX will fix your installation so that controls and components that come with VB5 work in the VB5 design environment. VBCMPFIX.EXE works ONLY with the components listed below, and will not affect any other third party controls you might be having problems with, or fix problems with any controls in the \Tools\Controls directory on the Visual Basic 5.0 CD.

Component List Ent Pro Lrn CCE
--------------------------------------------------------------------------
Microsoft Data Bound List Control X X X
Auto Connection Manager (AddIn) X X
Microsoft Tabbed Dialog Control X X X
Microsoft Winsock Control X X
Microsoft Comm Control X X
Microsoft RemoteData Control X
Microsoft Common Dialog Control X X X X
Microsoft Data Bound Grid Control X X X
Microsoft Windows Common Controls (1) X X X X
Microsoft PictureClip Control X X
Microsoft Flexgrid Control X X X
Microsoft Internet Transfer Control X X
Microsoft Chart Control X X
Microsoft MAPI Controls X X
Microsoft Windows Common Controls (2) X X
VB T-SQL Debugger (AddIn) X
Microsoft UserConnection
(ActiveX Designer) X
Microsoft Remote Data Object 2.0 X
Microsoft Multimedia Control X X
Microsoft Masked Edit Control X X
Microsoft Rich TextBox Control X X
Microsoft SysInfo Control X X
Data Access Objects 3.50
Object Library X X

How To Use
----------

VBCMPFIX is very simple to use. Run the self extracting VBC.EXE program, which will extract two files:

VBCMPFIX.EXE
ReadMe.Txt

Double click on VBCMPFIX.EXE from the Windows Explorer, or run it from the command line.

When VBCMPFIX launches, it will automatically detect which version of Visual Basic you have installed on your system. If you do not have Visual Basic installed, it will not allow you continue.

After it detects your version of Visual Basic, you can "Fix Install" or "Quit". Choosing "Fix Install" will update your system so that the controls and components that come with your edition of Visual Basic will work. The controls and components that are fixed is dependent upon the edition of Visual basic 5.0 you have installed.

After you have done this, close the utility and reboot your system. After rebooting, launch Visual Basic 5 and try using any controls you were having problems with.

Known Issues
------------

Users of Internet Explorer 4.x might notice that their desktop goes crazy after running VBCMPFIX.EXE. Bitmaps might become black and/or colors will be strange. Rebooting will solve this problem.

If you still cannot use controls after running VBCMPFIX.EXE, please contact Microsoft Visual Basic Technical Support. Re-run VBCMPFIX.EXE and write down the build number of the utility (given in the about box), and have that handy in case they ask for it. VBCMPFIX will not work on systems that have certain security settings, and Microsoft Visual Basic Technical Support will assist you in resolving this problem.

If you install Visual Basic on a network, sometimes security settings will carry over, and your system will not let VBCMPFIX.EXE to run correctly.

Updated : 02/28/98
Written by : Robert Young/Israel Burman/Robert Jacik

Regards.