The following is from Microsoft article Q187212 titled, "Windows Protection Error" After Upgrading to Windows 98".
This behavior can occur when all of the following conditions exist:
You have installed Windows 98 on a Toshiba Libretto 50CT, 70CT or 100CT computer.
Your computer has a standard port replicator.
You have a serial mouse attached to the standard port replicator.
The Windows 98 serial port driver (Serial.vxd) conflicts with Toshiba's power management driver (Pwrsave.vxd).
To resolve this issue, obtain the latest power management drivers for your computer from Toshiba's Web site. These drivers are available as L50pwsave.exe, L70pwsave.exe, and L100pwsave.exe. To work around this issue, follow these steps:
Restart your computer, press and hold CTRL until you see the Windows 98 Startup menu, and then select Safe Mode Command Prompt Only.
Use any text editor (such as Edit.com) to open the System.ini file in the Windows folder.
Locate the "device=pwrsave.vxd" line in the [386enh] section of the System.ini file, and then disable it by placing a semicolon (;) at the beginning of the line.
Save and then close the System.ini file.
Restart your computer.
Good luck,
Maxwell