The error is occurring because the Upgrade Advisor cannot create an HTML report. The slprj folder is usually a local, temporary folder that is writeable. Is the slprj folder mentioned writeable?
If I try the model, though, I see some issues with missing data, so it might be a more straightforward issue to fix without needing the full upgrade process. (Defining values for m, M, I, b , g, l in the MATLAB base workspace seems to make the model run).