Hi Rainer,
> I compared the definitions for the tabbing environment in the LaTeX core > between > an older installation and the current one: \kill is now a robust command. > Maybe that's the reason why it stopped working with tex4ht. It can be so :) > > In the meantime, you can use the `pic-tabbing` option. It converts the > > whole tabbing environment to picture. It seems that it is not affected > > by the error: > > Yes, using the "pic-tabbing" option works. Thanks for pointing this out. It is not a great solution in general, but it works well for math. Best regards, Michal