Just some followup:
1) per suggestion seen in similar problem on c.o.l.portable, I tried excluding higher ports (0xa00 up) in config.opts. No success, but not surprising since it always chose 0x300 anyway.
2) tried to get it up and running on Windows 95. No success, but this is likely due to my lack of W-95 expertise. It does seem to start up the card (lights on pigtail, beeps) but it can't see the network. Anyway it wanted files from Windows disk 19 and my set only goes to 13, so who knows what's going on there.
3) could the Tx timed out problem stem from problems elsewhere in the network? I ask because the whole network is new at once, and I haven't confirmed that the desktop (only other machine on network) really is able to communicate with network. I can ping to the laptop, it loses all packets but I do see the LED on pigtail blink at the ping rate.