Changing my username does seem to have fixed it, though only after a few tries. Thanks.

I'm now halfway there. I deleted my old Skype account in Admium, recreated it thanks to the latest version of the plugin (Skype API is again an option). . . but it never connects. It doesn't seem to care whether Skype's running, either. Perhaps it's just me. Would be good to know if anyone else is having more luck.

. . . except it doesn't seem to work. I've downloaded the new plugin and installed that; then, when that didn't work, deleted the plugin and reinstalled it; logged in and logged out; restarted my Mac; tried with Skype running and without Skype running - and Skype API will not appear as an option in the Add Account menu

That's great news.

Yep, Adium 1.2 has killed the plugin for me too.