"Solution Exception..." error / TT Toolbox

Hi All,

I put together a definition about six weeks ago using TT Toolbox's read excel component - I was able to use it on a few different workstations, and it ran without error. I'm now in a new office, and tried to run the script, but keep getting an error balloon at the "out" of the ReadXL component which says "Solution Exception: could not load file or assembly". I'm using Rhino 5 and Grasshopper 9.0076. I've tried uninstalling and reinstalling the TT Toolbox files, but still the same issue. I'm not sure how to proceed with troubleshooting - any suggestions?

Thanks,

Jane