The shell command
"/lrn-mdl-prod/build/75217/filter/tex/mimetex.linux" -e "/lrn-mdl-prod/moodledata/filter/tex/689b1ef372baac05d8d1b903e0bfbabb.gif" -- '\Large c_{t-1}'
returned status = 1
Image not found!
Please try the debugging script