Well, the Laptop is a Panasonic CF-25 and this phenomenon occurs with every network card (I tried several 3Com, one WaveLan silver and bronze and one NE2000 comp. noname card). The phenomenon is allways the same: First time (or after I do a init.d/pcmcia restart) everything is fine, after I eject one card and try to re-insert one (doesn't matter if its the same or another one), I get a low beep/high beep and in the logfiles the card is recognized as a "unknown memory card". Apart from that there`s nothing spezial in the logfiles.
The same cards work fine in any combination on another laptop (Dell xyz)