I have been experimenting with tagging. But my attempts with two files now
have generated this sort of error message:

lua error       > lua error on line 62 in file c_Int-A002_Acerbi.tex:


.../ConTeXt/tex/texmf-context/tex/context/base/strc-tag.lua:407: bad
argument #2 to 'lpegmatch' (string expected, got boolean)

stack traceback:

[C]: in function 'lpegmatch'

.../ConTeXt/tex/texmf-context/tex/context/base/strc-tag.lua:407: in
function 'strippedtag'

.../ConTeXt/tex/texmf-context/tex/context/base/back-exp.lua:740: in
function <.../ConTeXt/tex/texmf-context/tex/context/base/back-exp.lua:739>

(...tail calls...)

Could someone tell me what this means—is there are error in my encoding or
a problem in lua?

Alan