Hola!

1. Looks like you are using CGI. I was in a similar position 2 years ago for my year of professional experience out of university. I was adding some reports to my team's Bugzilla server. Fortunately it ran on Mandrake Linux, so I used Exceed and KATE for development and never had to install any new modules. Unfortunately, Bugzilla has it's own 'non-standard' CGI framework, so...
2. Ovid's CGI tutorial: http://users.easystreet.com/ovid/cgi_course/
3. You also need to get your web server sorted. I assume your desktop Win98 box is for development purposes only and I'm guessing that since you are the student, you have the spare PC that could not be upgraded, 2 of my student friends had the spare Win95 PCs when they worked here :( I can only say search the Windows PWS help files and have a look at ActivePerl's HTML documentation, sorry.
4. Stop apologising!
5. ???
6. Profit!
7. Oh wait... This isn't /.
8. $my{XP} > $my{Perl}{skill}, so I would suggest you read the license of the sample scripts you have downloaded and ask your manager/mentor if you can just plug them straight in. If (s)he says OK, then you have a pretty good tool that you just need to glue together. If this is meant to be learning exercise then have some fun and do it your way.
9. Check Perl's GD::Graph for your reports, or output your numbers to Excel format and use VB to do your graphs

Buenas nachos :)