Had the same Problem. Solved it by first installing PNP infrared device.After this you have to enter Bios Setup and configure your serial port B for IRDA. This is what Fujitsu say about it:
"I cannot communicate with an IrDA peripheral in Windows 95/98. What's wrong?
The first thing to make sure of is that the peripheral you are trying to communicate with is IrDA 1.0 or 1.1 compatible.
Next, you should check the BIOS configuration of the IrDA port. The serial port B should be set to IrDA enabled, with avalid I/O address set.
After you?ve done this, you need to start the Windows IrDA monitor by using the infrared icon in the control panel. Alsomake sure that the infrared monitor is not disabled. If infrared is disabled, you will need to go to the Options tab andselect the related COM port. Once you connect with another IrDA device, Windows will make a sound and a description of theIrDA peripheral will appear in the infrared monitor."
Hope that helps