The shell command
"/lrn-mdl-prod/build/75217/filter/tex/mimetex.linux" -e "/lrn-mdl-prod/moodledata/filter/tex/c9af8e1fcd4e3c3eccdbc3030aea6a40.gif" -- '\Large h_{t-1}'
returned status = 1
Image not found!
Please try the debugging script