> "File error: data may have been lost."

This error is explained in Step 11 of the Methodology in the Chart documentation. You can also see how it is dealt with in the example files. The charting documentation isn't exhaustive but it is important to try to follow it as closely as possible.

> For instance, instead of being "download" it is, "#@$#awnload."

I can't reproduce this. Upgrade to the latest version of Spreadsheet::WriteExcel and see if the problem persists. If it does, see if you can post an example based on the bug_report.pl program in the examples directory of the distro.