I'm new to ConTeXt and try to use the module typearea (https://modules.contextgarden.net/cgi-bin/module.cgi/action=find/name=typearea).
But the example doesn't work:


I got:

loading         > Something like KOMA-TypeArea
tex error       > tex error on line 89 in file /usr/local/texlive/2023/texmf-dist/tex/context/third/typearea/t-typearea.tex: Missing number, treated as zero

<to be read again>
<macro> \TA@alphabets
     \par \PageWidth =\dimexpr \paperwidth -\TA@bcor \relax \par \edef \Ratio {\withoutpt {
    \the \dimexpr 2\paperheight /(\PageWidth /32768)\relax }} \par \setbox \scratchbox \hbox {\dorecurse {26}{\character \recurselevel }} \Width =\dimexpr \TA@alphabet
<line 5.89>

79          height=\the\Height,
80          width=\the\Width,
81          header=2\lineheight,
82          headerdistance=\lineheight,
83          footer=2\lineheight,
84          footerdistance=3\lineheight,
85          topspace=\Top]
86     }
87     \protect
89 >>  \setupTypeArea[bcor=0pt,oneside=no,alphabets=2.6]
91     \doifnotmode{demo}{\endinput}
93     %D Usage example:
94     \usemodule[typearea]
95     \setupTypeArea[bcor=0mm,alphabets=3.1]
96     \setuppagenumbering[alternative=doublesided]
97     \starttext
98     \dorecurse4{\framed[width=\textwidth,height=\textheight]{test}\page}
99     \stoptext
A number should have been here; I inserted '0'. (If you can't figure out why I
needed to see a number, look up 'weird error' in the index to The TeXbook.)
mtx-context     | fatal error: return code: 1

Line 89 in the module should be the problem. But how can I solve it? I think some lines in the module should be commented out. (An example directly in the module?)

I thank you for any hint.