Bri: I believe, because JTablet's still in alpha, it's going to have bugs and glitches. If it's not working for you, unless Draca knows of a way to fix it, I'm not sure it can be fixed until Cellosoft makes a better version, an alternate is made available, and/or Mac starts playing nice with Java. You can try uninstalling it and reinstalling and testing until it decides to work (if it does), but at the moment, I neither know of any fixes, and I can't find any. ^^;
Doodly: F-Secure has an online virus scan here, and Kaspersky's got another here if you want extra assurance, if you don't have an antivirus already on your computer. If you do have one, please use it. It might not be the problem with the Oekaki (you might be able to fix that by switching to V2 here), but I'd still worry about making absolutely sure there aren't any viruses on your system.
F-Secure is able to remove any infections, Kaspersky's a standalone application that provides enough info to help you remove malware/viruses yourself, if you're good with looking stuff up.