This issue can occur on a PowerBook 5300 or PowerBook 1400, if the Apple Telecom 3.2.2 Serial Modem Software and Mac OS 8.0 or 8.1 are installed.
The issue is purely cosmetic; the PC card will continue to function normally even though the name that appears on the desktop is unreadable.
Ejecting and re-inserting the PC card should alleviate the issue temporarily.