Hello Philippe,
In the download section, under Telemac, you have a folder called sources, where you have... the sources and the installation guide.
In bedload_formula, qsform is called without argument, so all what you use in qsform must be in declarations_sisyphe, whereas in bedload_formula, you have arguments with local names like QSS and QSC. So you need to use the original names in qsform.
Regards,
Jean-Michel