Hello @a133ya
When I encounter an unknown reference error, I first check for accidental spaces in the Excel file. Then I check the spelling and capitalisation of the file name and file extension. While ‘Filename.Ext’ and ‘Filename.Ext’ are treated alike on a Windows 11 system, they are two separate files on a Unix system. The name you use in your condition file (stimulus1.jpg) must match the filename in filename (stimulus) and extension (.jpg).
see here Wakefield's Daily Tips - #26 by wakecarter
I also turn off randomisation to check whether the error affects one file specifically or all files. If it is the latter, the column name is probably spelled incorrectly.
Does the call from one condition file to subsequent condition file work?
Best wishes Jens