It's a known issue with some installations of IE 6.0 on Windows 98, and there's not always a fix.
But do try the following things:
Empty your cache folders in MS-DOS:
Go to Start/shutdown, and choose 'restart the computer in MS-DOS mode'.
Type the following lines, pressing ENTER after each one:
cdcd windows
smartdrv
deltree tempor~1
deltree history
deltree cookies
NOTE: Press Y if you are prompted to confirm any deletion
Type win (or 'exit') followed by clicking enter in order to return to Windows.
If no joy, try repairing IE: Control Panel > Software Add\Remove > MS Internet Explorer > Remove > Repair IE
You might also try reinstalling IE 6.
Now the first thing to do is to fool Windows into believing you're running an older version of IE/OE, or it won't let you reinstall.
You can do that by editing the version info:
Go to Start > Run, and type Regedit.
Drill down to HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer.
Doubleclick the 'version' value in the right pane, and edit it to change the 6.0 part to 5.5
IE Setup will now think you're running an older version of Internet Explorer, and you'll be able to run IE setup and reinstall IE in its entirety.
Don't forget to shut down as many running programs as possible, especially your antivirus, before starting the download and install.
Finally, if all fails, try restoring the original version of Oleaut32.dll:
Go to Start/run, and type SFC.
Choose 'Extract One File From Installation Disk'.
Type oleaut32.dll, not worrying about its location. Then, click Start.
Next to 'Restore From', type in or browse for the file’s location, which is probably in the Win98 folder of your installation CD-ROM (typically D:\Win98), or in your Windows\Options\Cabs folder, as the case may be.
Then, next to 'Save File In', enter C:\Windows\System, and click OK. System File Checker looks for the file, saves it as you requested, and then tells you that 'the file has been successfully extracted'.
Tony