Just like to add to what others have said... In VB,Java,.NET,etc the standard way of doing client/server is to have a "thick", native Windows client.

In Perl, Ruby, etc. the standard way is to make a Web application. The advantages are numerous, especially with a large user base (no need to install), and especially where you have some control over what browser they're using (make sure no one's using IE4).

With the advent of things such as Rich Text Edits, and AJAX (so long as it's used in a sensible manner) you no longer have a lot of restrictions in the complexity of your user interface.

The fact that you're running Win98 on your workstations is even more of an argument for thin client. You can push most of the processing to a big beefy, clustered, loadbalanced, etc. server running Linux (or Windows server if you must), and install nothing but a browser on the workstations. Any performance issues can be tuned in one place (i.e. the server's OS, the webserver, etc. which are designed to be configured in this manner).

I think once you've made the decision to go with a thin client, then the choice of language becomes much less of an issue.