Don't worry. This problem is because in the example I gave you I use the variable name $excel which I found more descriptive than $e. Using easier to understand variable names helps when someone else looks at your code, or you haven't looked at it in a long time. By copying and pasting this one line then you'd also have to replace the other instances of $e with $excel.
The quick and dirty way to fix this is to replace $excel with $e. From the command prompt can you run the following and post the output?
cpan -D Spreadsheet::ParseExcel
