Comms Port Trouble

Am running a program called Telix which cannot detect comms port 1 or 2.
There are no hardware faults (tested using other devices and comm ports work fine). The comm port settings are correct (checked them against the comm port settings from the system). Telix is not faulty (tried it on 2 different laptops and they worked fine).
Hasn’t worked on two of the PC’s I’ve tried however.
OS = Windows 98 SE
machine = Pentium III 663MHz
What could the problem be? Thanks