I've had similar problems with Xircom cards with Tosh's in the past, but generally with 95. I had to remove it totally including manually from the registry as in the uninstal text file that comes with it.
If it's a DOS boot disk try putting a memory exclusion in the config.sys as I had that problem before.(I think this is also documented somewhere on the disk, sorry to be so vague, but this is from memory from 2 years ago)
Also try dissabling the IR port or built in modem if it has one.
I hope this is of some help, I've not had too many fond memories of Xircom!