1) Is it Office 2000 that you are using? In that case, this error occurs because of a compatibility issue between Outlook and your OS. To fix this, copy the wab.dll file from your system folder to your system32 folder:
- Browse to C:\Windows\System on your PC
- Locate the wab32.dll and wab32res.dll files
- Copy both files to your clipboard
- Paste both files into your C:\Windows\System32 folder
- Click Start > Run
- Type “cmd” in the box without quotes.
- In the window that appears, type the following comands and hit Enter after each:
2) If nothing works, try reinstalling OE or switch to Windows live Mail, its pretty nifty.