Quoting from
http://www.smartcomputing.com/techsupport/detail.aspx?guid=&ErrorID=22758 :
Error Message:
The add-in C:\Windows\System32\Fxsext32.dll could not be installed or
loaded. This problem may be resolved by using Detect and Repair on the
Help menu.
Translation:
This message is received when using Outlook 2003 to send email. The
error message indicates there’s an apparent problem with the faxing
software, WinFax Pro 10.03.
Solution:
The first course of action is to follow the remedy prescribed by the
error message itself. You should open the Help menu in Outlook 2003 and
select the Detect And Repair option. (Clicking the tiny arrows located
at the bottom of the Help menu will expose all of the menu’s commands.)
On-screen instructions will guide you through the process of identifying
and fixing common problems with the email client. When the repair is
complete, you should reboot your PC and try to send email.
If the problem persists, the next step is to remove the Microsoft Fax
component of WinXP in order to eliminate potential conflicts between it
and WinFax Pro. You can remove the built-in utility by opening the
Control Panel, clicking the Add Or Remove Programs icon, and clicking
the Add/Remove Windows Components option. The Windows Components Wizard
will appear on-screen. Scan the options presented in the Components list
for one labeled Fax Services. When you find it, deselect it and click
Next. Follow the remaining on-screen instructions to finish the process.
Reboot the PC when you finish. Again, try to send email to determine
whether the issue is resolved.
If neither of these suggestions works, a final remedy is to replace the
Fxsext32.dll file with a new copy from the Windows installation CD-ROM.
You can accomplish this task with help from the System File Checker
utility. From the Start menu, select Run, type sfc /scannow in the
field, and click OK. You may be prompted to insert the installation
CD-ROM in the optical drive if you haven’t put it there already. The
System File Checker will scan the contents of the WINDOWS\SYSTEM32
folder and update any corrupted, outdated, or missing DLL (dynamic-link
library) files. When the process is complete, reboot your PC.